From dd6ef5922a5effcf307b863b5e391015a32e7e7b Mon Sep 17 00:00:00 2001 From: Vishakh Kumar Date: Mon, 14 Jul 2025 01:42:20 +0400 Subject: [PATCH] Stuff --- .DS_Store | Bin 0 -> 10244 bytes BibMine.bib | 13 + Bibliography.bib | 39 + LICENSE | 21 + Makefile | 88 ++ README.md | 14 + Thesis.bbl | 3 + Thesis.maf | 15 + Thesis.org | 3 + Thesis.pdf | 3 + Thesis.tex | 1260 ++++++++++++++++++++++++++ Untitled.ipynb | 3 + cavitation_erosion_data.xlsx | Bin 0 -> 56889 bytes cavitation_models.org | 16 + literature_review.org | 3 + references.bib | 3 + rig.org | 16 + stellite.org | 57 ++ thesis_original.org | 1650 ++++++++++++++++++++++++++++++++++ touchme | 0 20 files changed, 3207 insertions(+) create mode 100644 .DS_Store create mode 100644 BibMine.bib create mode 100644 Bibliography.bib create mode 100644 LICENSE create mode 100644 Makefile create mode 100644 README.md create mode 100644 Thesis.bbl create mode 100644 Thesis.maf create mode 100644 Thesis.org create mode 100644 Thesis.pdf create mode 100644 Thesis.tex create mode 100644 Untitled.ipynb create mode 100644 cavitation_erosion_data.xlsx create mode 100644 cavitation_models.org create mode 100644 literature_review.org create mode 100644 references.bib create mode 100644 rig.org create mode 100644 stellite.org create mode 100644 thesis_original.org create mode 100644 touchme diff --git a/.DS_Store b/.DS_Store new file mode 100644 index 0000000000000000000000000000000000000000..aaa2ce0022903cff0ecfc42480da481b64c2ddfa GIT binary patch literal 10244 zcmeHM&x;&I6n?!ko0(-J%qAN5*bsyqHgR?pH3%}Gc ztjoXzMMOnB`zHuFD1yI0^q?p8;6V?$2wrmV90W1=Rdr2wRd>x~dPPvFhVEC>@4c$; zeO3LsUkwpi>;2j)kxfK-oJ_YJZGNDQI)MAw zLY9Oa1(Lg>&!Bp+gsUY=3@dPl-e%^IB_T(F4BW{I+{qFnTcSd-_~`Jnxj9*-K$@#z zz%YtTz2BZ1dj_Z+}sk|MtwZzFU4R zm3@0Rfh7yv4RWcc;#_7aA=JsZ-oG)}dUuKAlJpS{on9T+M%Q!%{IezI&!Q)J0%ABV4RpaD%7ZInA2v5?>*w10{vi+To zCb9{Zax5#4hOtbvj%MQS)*8H7Izwf;Naw19Zdw+wB#LKUs5`?EIk|j>X)I zjS57?}qR7Dy~=Wa0jvG?6pjg1+6qfh*PZwA0wbj$Z6?=bmZ4EyjdAK+nF68e!{@~*moGZOpy*{> zUoF2hUdJ(;2-_qZ4ZdSQ@d{RC1?$lT8jnANeW1DujYB&uCvcrd4Gnjx{N*^FI1$E? zvX3avgZ81}VM*}7a#0IymUkSqDrhlwn%XQhgO?ohXOD$3&*T|Jn$A-bUyh!_Og0cp z2hqhcD$nvU3mNzC&+d(LeZnfjIN3_YV`KSa{kxpqMiLEEt9lvB&e@Pdr4Kn@PqI;Q z@Nx23^KCxgJ7`s?rL6JHQMUJvQOHFgm@)9e&n3q=NO9;jU4dNrOM z9y+UPWh}3MaQj#Bj+6XlX7m=y_(747$M`%qQI}_cJ%ty_ZE;>=HZqnQ*PY)4mPB7N zqG@(2E?$ikfD0LuqwDhL(!sUEzZ+bZvs9eteg@9F`pCGSKXq-q)@SgG<~NO>8rNk& zqzq!f^Qoe@K8Z9k#y^g{_u&t3@--*?WJZ%(bv({v4)a>a6X@Vti|2#k#~3$eA&>w0 z)93GB3cg7bRuLnUtyDZC3`PsU)5A=9K*Qz}nEoeU9-7FMS)M!kwLX5C@e8-U`$){V zrayW1r&}t_&y_H+j``TPN)FGJ%fHF-#Ts8LKfZ=OViq#;o6j7(Bl1APDq1U(trW!c z3qzd2|DsqS3X7CkiZt^0cdl>zDaIFmGFwTlIv#&k*qG)p3`}Dn6DV!A|NrFV|Np0T zVRVK8!@z%>0V}&%-dslzOO82R6)#7c V&QlX#tZr9hG4(&{j=xd={{^{E!esye literal 0 HcmV?d00001 diff --git a/BibMine.bib b/BibMine.bib new file mode 100644 index 0000000..56d32a0 --- /dev/null +++ b/BibMine.bib @@ -0,0 +1,13 @@ +@misc{C05, + author = {Awesome, F.}, + year = {2005}, + title = {Frank}, + keywords={mine} +} + +@misc{C06, + author = {Awesome, F.}, + year = {2006}, + title = {frank, but lowercase}, + keywords={mine} +} \ No newline at end of file diff --git a/Bibliography.bib b/Bibliography.bib new file mode 100644 index 0000000..cc87471 --- /dev/null +++ b/Bibliography.bib @@ -0,0 +1,39 @@ +@misc{C01, + author = {Anglois, B.}, + year = {2005}, + title = {This is a paper}, + keywords={biblio} +} + +@misc{C02, + author = {Ovalie, F.}, + year = {2005}, + title = {Robert}, + keywords={biblio} +} + +@misc{C03, + author = {Cuthor, C.}, + year = {2003}, + title = {Charlie}, +} + +@misc{C04, + author = {Absol, E.}, + year = {2005}, + title = {Danger}, +} + +@misc{C07, + author = {Andre, S.}, + year = {2003}, + title = {Orange}, + keywords={biblio} +} + +@misc{C08, + author = {Kor, W.}, + year = {2001}, + title = {Poule}, + keywords={biblio} +} \ No newline at end of file diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..ea6715b --- /dev/null +++ b/LICENSE @@ -0,0 +1,21 @@ +MIT License + +Copyright (c) 2021 Dorian Gouzou + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..e744016 --- /dev/null +++ b/Makefile @@ -0,0 +1,88 @@ +### latex.makefile +# Author: Jason Hiebel + +# This is a simple makefile for compiling LaTeX documents. The core assumption +# is that the resulting documents should have any parameters effecting +# rendering quality set to theoretical limits and that all fonts should be +# embedded. While typically overkill, the detriment to doing so is negligible. + +# Targets: +# default : compiles the document to a PDF file using the defined +# latex generating engine. (pdflatex, xelatex, etc) +# display : displays the compiled document in a common PDF viewer. +# (currently linux = evince, OSX = open) +# clean : removes the obj/ directory holding temporary files + +PROJECT = Thesis +default: obj/$(PROJECT).pdf + +display: default + (${PDFVIEWER} obj/$(PROJECT).pdf &) + + +### Compilation Flags +PDFLATEX_FLAGS = -halt-on-error -output-directory obj/ + +TEXINPUTS = .:obj/ +TEXMFOUTPUT = obj/ + + +### File Types (for dependancies) +TEX_FILES = $(shell find . -name '*.tex' -or -name '*.sty' -or -name '*.cls') +BIB_FILES = $(shell find . -name '*.bib') +BST_FILES = $(shell find . -name '*.bst') +IMG_FILES = $(shell find . -path '*.jpg' -or -path '*.png' -or \( \! -path './obj/*.pdf' -path '*.pdf' \) ) + + +### Standard PDF Viewers +# Defines a set of standard PDF viewer tools to use when displaying the result +# with the display target. Currently chosen are defaults which should work on +# most linux systems with GNOME installed and on all OSX systems. + +UNAME := $(shell uname) + +ifeq ($(UNAME), Linux) +PDFVIEWER = evince +endif + +#ifeq ($(UNAME), Darwin) +#PDFVIEWER = open +#endif + + +### Clean +# This target cleans the temporary files generated by the tex programs in +# use. All temporary files generated by this makefile will be placed in obj/ +# so cleanup is easy. + +clean:: + rm -rf obj/ + +### Core Latex Generation +# Performs the typical build process for latex generations so that all +# references are resolved correctly. If adding components to this run-time +# always take caution and implement the worst case set of commands. +# Example: latex, bibtex, latex, latex +# +# Note the use of order-only prerequisites (prerequisites following the |). +# Order-only prerequisites do not effect the target -- if the order-only +# prerequisite has changed and none of the normal prerequisites have changed +# then this target IS NOT run. +# +# In order to function for projects which use a subset of the provided features +# it is important to verify that optional dependancies exist before calling a +# target; for instance, see how bibliography files (.bbl) are handled as a +# dependency. + +obj/: + mkdir -p obj/ + +obj/$(PROJECT).aux: $(TEX_FILES) $(IMG_FILES) | obj/ + xelatex $(PDFLATEX_FLAGS) $(PROJECT) + +obj/$(PROJECT).bbl: $(BIB_FILES) | obj/$(PROJECT).aux + bibtex obj/$(PROJECT) + xelatex $(PDFLATEX_FLAGS) $(PROJECT) + +obj/$(PROJECT).pdf: obj/$(PROJECT).aux $(if $(BIB_FILES), obj/$(PROJECT).bbl) + xelatex $(PDFLATEX_FLAGS) $(PROJECT) diff --git a/README.md b/README.md new file mode 100644 index 0000000..a7f1391 --- /dev/null +++ b/README.md @@ -0,0 +1,14 @@ +HW_LaTex_thesis_template +======================== + +Thesis LaTex template based on the submission guidelines of Heriot-Watt University, that I have personally updated. +Aside: these guidelines are mainly for PhD theses but are also valid for non PhD research dissertations/theses (specifically for those writing up an MRes or MPhil). + +The template has been updated to support subfiles (for rendering each chapter independently of the full document) - a feature helpful for theses with lots of images, especially large ones. Other small tweaks are applied such as support for using acronyms in the document with the acro package, replacing the more cumbersome glossaries package. + +Additionally the university shield is now updated to something I cropped and cleaned myself, rather than the previously included one which looked like it was traced lovingly in microsoft word. + +Lastly, links to the university guidance are included, and text in each section describe the relevant portion of the guidance. + +November 2021: I have updated the documentation to be clearer about cleveref, and have added biblatex which allows per-chapter bibliographies. To-do notes have also been added. More mathematics support was added in out of the box too. +-Alexandre Coates, November 2021 diff --git a/Thesis.bbl b/Thesis.bbl new file mode 100644 index 0000000..0545499 --- /dev/null +++ b/Thesis.bbl @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:20e3ca750685955437a238135b134c9815a1e6c2bb05ce05bfe6ea4b6c00fdf1 +size 239239 diff --git a/Thesis.maf b/Thesis.maf new file mode 100644 index 0000000..a7d367a --- /dev/null +++ b/Thesis.maf @@ -0,0 +1,15 @@ +Thesis.mtc +Thesis.mtc0 +Thesis.mtc13 +Thesis.mtc12 +Thesis.mtc11 +Thesis.mtc10 +Thesis.mtc9 +Thesis.mtc8 +Thesis.mtc7 +Thesis.mtc6 +Thesis.mtc5 +Thesis.mtc4 +Thesis.mtc3 +Thesis.mtc2 +Thesis.mtc1 diff --git a/Thesis.org b/Thesis.org new file mode 100644 index 0000000..fc8d795 --- /dev/null +++ b/Thesis.org @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9dfd78cc18fae4302f8eedc3aa3ccee07acd5b8eece5b11548b77bddf4eab729 +size 135416 diff --git a/Thesis.pdf b/Thesis.pdf new file mode 100644 index 0000000..af2e219 --- /dev/null +++ b/Thesis.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:308ef600c06f6dea548c79436f607393bdfe0487bbd551f396bf7275e8606ff7 +size 319553 diff --git a/Thesis.tex b/Thesis.tex new file mode 100644 index 0000000..d6d3aa2 --- /dev/null +++ b/Thesis.tex @@ -0,0 +1,1260 @@ +% Created 2025-06-25 ر 19:25 +% Intended LaTeX compiler: pdflatex +\documentclass[11pt]{report} +\usepackage[utf8]{inputenc} +\usepackage[T1]{fontenc} +\usepackage{graphicx} +\usepackage{longtable} +\usepackage{wrapfig} +\usepackage{rotating} +\usepackage[normalem]{ulem} +\usepackage{amsmath} +\usepackage{amssymb} +\usepackage{capt-of} +\usepackage{hyperref} +\graphicspath{{expt/}} +\usepackage{afterpage} +\usepackage{pdflscape} +\usepackage{booktabs,caption} +\usepackage{longtable} +\usepackage{makecell} +\usepackage[flushleft]{threeparttablex} +\usepackage{multirow} +\usepackage{caption} +\usepackage{booktabs} % Added for nicer rules +\usepackage{textcomp} +\usepackage{mathtools} +\usepackage{graphicx} % include graphics +\usepackage{fancyhdr} % layout +\usepackage[english]{babel} +%\usepackage[utf8]{inputenc} +\usepackage[T1]{fontenc} % font +\usepackage{csquotes} +%\usepackage[defernumbers=true, sorting=none]{biblatex} +\usepackage[defernumbers=true, bibstyle=ieee, citestyle=numeric-comp, backend=biber, maxbibnames=999]{biblatex} + +\usepackage{setspace} % spacing +% \usepackage[left=4cm,right=2cm,top=2cm,bottom=2cm]{geometry} +\usepackage{mathptmx} % looks like times new roman +\usepackage{slantsc} +\usepackage{titlesec} +\usepackage{mfirstuc} +\usepackage{calc}% http://ctan.org/pkg/calc +\usepackage[acronym, nonumberlist]{glossaries} % https://www.overleaf.com/learn/latex/Glossaries +\usepackage{hyperref} % https://ctan.org/pkg/hyperref +\usepackage{pdfpages} +\usepackage{float} +\usepackage{minitoc} +\usepackage{pdflscape} +%% prefer than direct use in usepackage geometry +%% A4 layout in point is % 595x842 +%% default value +\setlength{\hoffset}{0pt} +\setlength{\voffset}{0pt} +%% height +%% 72 - 60 + 20 + 25 = 57 +\setlength{\topmargin}{-60pt} +\setlength{\headheight}{20pt} +\setlength{\headsep}{25pt} +\setlength{\footskip}{30pt} +%% width +%% 72 + 32 + 10 = 114pt = 40mm +\setlength{\oddsidemargin}{32pt} +\setlength{\evensidemargin}{32pt} +\setlength{\marginparsep}{10pt} +%% size text +\setlength{\textheight}{728pt} +\setlength{\textwidth}{425pt} +%% style +%% preliminary, just roman pagination + empty header +\fancypagestyle{preliminary}{ +\renewcommand{\headrulewidth}{0pt} +\fancyhead[RCL]{} +\pagenumbering{Roman} +} +%% chapter/classic text style +\fancypagestyle{chapter}{ +%% title of the chapter, left header, no uppercase, 10 pt, italics, no bold +\fancyhead[L]{\normalfont\itshape\fontsize{10pt}{12pt}\selectfont\nouppercase{\leftmark}} +\fancyhead[R]{} + +\fancyfoot[C]{\thepage} +\renewcommand{\headrulewidth}{0.4pt} +\renewcommand{\footrulewidth}{0pt} +\pagenumbering{arabic} +} +%% define length and scaling for baseline +\newcommand{\headingBaseline}{12} +\newcommand{\headingBaselineDiv}{10} +\newlength{\chapterFontSize} +\newlength{\sectionFontSize} +\newlength{\subsectionFontSize} +\newlength{\chapterBaseline} +\newlength{\sectionBaseline} +\newlength{\subsectionBaseline} +%% change those value if you want to change the chapter/section/subsection font size +\setlength{\chapterFontSize}{14pt} +\setlength{\sectionFontSize}{12pt} +\setlength{\subsectionFontSize}{12pt} +%% automatic computation for baseline, rule of thumb is 1.2 +\setlength{\chapterBaseline}{ \chapterFontSize * \headingBaseline / \headingBaselineDiv} +\setlength{\sectionBaseline}{ \sectionFontSize * \headingBaseline / \headingBaselineDiv} +\setlength{\subsectionBaseline}{ \subsectionFontSize * \headingBaseline / \headingBaselineDiv} +%% headings +%% Chapter, 14-point, bold +\titleformat{\chapter}[display] +{\normalfont\bfseries\fontsize{\chapterFontSize}{\chapterBaseline}\selectfont}{\chaptertitlename\ \thechapter}{14pt}{} +%% capitalised initial letter, +% \titleformat{\chapter}[display] +% {\normalfont\bfseries\fontsize{\chapterFontSize}{\chapterBaseline}\selectfont}{\chaptertitlename\ \thechapter}{14pt}{\capitalisewords} +%% left|above|below +\titlespacing{\chapter}{0pt}{10pt}{25pt} +%% Section, 12-point +\titleformat{\section}[hang] +{\normalfont\bfseries\fontsize{\sectionFontSize}{\sectionBaseline}\selectfont}{\thesection}{5pt}{} +%% capitalised initial letter +% \titleformat{\section}[hang] +% {\normalfont\bfseries\fontsize{\sectionFontSize}{\sectionBaseline}\selectfont}{\thesection}{5pt}{\capitalisewords} +%% left|above|below +\titlespacing{\section}{0pt}{25pt}{15pt} +%% Subsection, 12-point, italic +\titleformat{\subsection}[hang] +{\normalfont\bfseries\itshape\fontsize{\subsectionFontSize}{\subsectionBaseline}\selectfont}{\thesubsection}{5pt}{} +% \titleformat{\subsection}[hang] +% {\normalfont\bfseries\itshape\fontsize{\subsectionFontSize}{\subsectionBaseline}\selectfont\MakeLowercase}{\thesubsection}{5pt}{\makefirstuc} +%% left|above|below +\titlespacing{\subsection}{0pt}{20pt}{10pt} +%% table of content +\renewcommand{\contentsname}{Table of Contents} +\setcounter{tocdepth}{2} +\setcounter{secnumdepth}{2} +%% list of figure +\renewcommand*\listfigurename{Figure table} +%% init gloassaries +%% noidx cause otherwise we have to do a normal glossary, compile, then remove it so it is cached +%% because we only use acronym +\makenoidxglossaries +%% bibliography config +%% https://tex.stackexchange.com/a/6977 +\DeclareBibliographyCategory{cited} +\AtEveryCitekey{\addtocategory{cited}{\thefield{entrykey}}} +\addbibresource{Bibliography.bib} +\addbibresource{BibMine.bib} +\addbibresource{references.bib} +%% hyperref setup +\hypersetup{ +colorlinks = true, +linkcolor = blue, % normal internal links, like ref, can be black tbh +citecolor = blue, % bibliographical links +urlcolor = blue, % linked urls +filecolor = black % url which open local files +} +%% modified reference function +%% https://tex.stackexchange.com/a/438998 +\newcommand\eref[1]{Equation~(\ref{#1})} +\newcommand\tref[1]{Table~\ref{#1}} +\newcommand\fref[1]{Figure~\ref{#1}} +%% 1.5 line spacing +\setstretch{1.5} +%% The title of Thesis +\newcommand{\thesisTitle}{How to make a thesis following the guideline with more text to have two lines} +%% Number of Volume, if more than one +%% not sure how it works out with latex tbh +\newcommand{\numberVolume}{2} +%% The number of this volume +\newcommand{\actualVolume}{1} +%% The author's name (you) +\newcommand{\authorName}{A Good Name} +%% Distinctions/Qualifications if desired +\newcommand{\distinction}{The awesome} +%% The qualification +\newcommand{\degreeQualification}{Doctor of Philosophy} +%% The institution +\newcommand{\institution}{Some weird institute no one ever heard about} +%% The school +\newcommand{\school}{School of Latex and Writing} +\newcommand{\university}{Heriot-Watt University} +%% Month of submission +\newcommand{\monthDate}{September} +%% Year of submission +\newcommand{\yearDate}{2042} +\usepackage{subfiles} +\newacronym{sem}{SEM}{Scanning Electron Microscope/Microscopy} +\newacronym{edx}{EDX}{Energy-Dispersive X-ray} +\newacronym{xrd}{XRD}{X-ray Diffraction} +\newacronym{hv}{HV}{Hardness Vickers Scale} +\newacronym{hip}{HIP}{Hot Isostatically Pressed} +\newacronym{fcc}{FCC}{Face Centred Cubic} +\newacronym{hcp}{HCP}{Hexagonal Close Packed} +\newacronym{se}{SE}{Secondary Electrons} +\newacronym{bse}{BSE}{Backscatter Electrons} +\newacronym{pdf}{PDF}{Powder Diffraction File} +\date{} +\title{} +\hypersetup{ + pdfauthor={Vishakh Pradeep Kumar}, + pdftitle={}, + pdfkeywords={}, + pdfsubject={}, + pdfcreator={Emacs 30.1 (Org mode 9.7.29)}, + pdflang={English}} +\begin{document} + +\dominitoc + + + +\pagestyle{empty} + +\begin{center} +\vspace*{15pt}\par +\setstretch{1} +% \hrule +% \vspace{10pt}\par +\begin{spacing}{1.8} +%% you can replace by \MakeUppercase if you want uppercase +{\Large\bfseries\MakeLowercase{\capitalisewords{\thesisTitle}}}\\ +\end{spacing} +% \hrule +% This thesis is composed of \numberVolume volumes. This one is the number \actualVolume. + +\vspace{40pt}\par +\includegraphics[width=140pt]{Figures/logo.png}\\ +\vspace{40pt}\par + + +{\itshape\fontsize{15.5pt}{19pt}\selectfont by\\}\vspace{15pt}\par + +{ +\Large \authorName +% , \distinction +}\vspace{55pt}\par + +{ +\large Submitted for the degree of \\ \vspace{8pt} \Large\slshape\degreeQualification\\ +} + +\vspace{35pt}\par + +{\scshape\setstretch{1.5} \institution\\ \school\\ \university\\ +} + +\vspace{50pt}\par + + +{\large \monthDate\ \yearDate} + +\vfill + +\begin{flushleft} +\setstretch{1.4}\small +The copyright in this thesis is owned by the author. Any quotation from the thesis or use of any of the information contained in it must acknowledge this thesis as the source of the quotation or information. +\end{flushleft} +\end{center} + + +\clearpage +\begin{center} +\LARGE\textbf {Abstract} +\end{center} +\vspace{5pt} + +\noindent +In accordance with the Academic Regulations the thesis must contain an abstract preferably not exceeding 200 words, bound in to precede the thesis. The abstract should appear on its own, on a single page. The format should be the same as that of the main text. The abstract should provide a synopsis of the thesis and shall state clearly the nature and scope of the research undertaken and of the contribution made to the knowledge of the subject treated. There should be a brief statement of the method of investigation where appropriate, an outline of the major divisions or principal arguments of the work and a summary of any conclusions reached. The abstract must follow the Title Page. + + +\clearpage +\begin{center} +\LARGE\textbf {Dedication} +\end{center} +\vspace{5pt} + +If a dedication is included then it should be immediately after the Abstract page.\par +I don't what it is actually. + +\clearpage +\begin{center} +\LARGE\textbf {Acknowledgements} +\end{center} +\vspace{5pt} + +\noindent I wanna thanks all coffee and tea manufacturers and sellers that made the completion of this work possible. + +{ +\setstretch{1} +\hypersetup{linkcolor=black} +\tableofcontents + +\listoftables % optional + + +\listoffigures % optional + + +\glsaddall % this is to include all acronym. You can do a sort of citation for acronym and include only the one you use, Look at the glossary package for details. +\printnoidxglossary[type=\acronymtype, title=Glossary] % optional +} + + +\clearpage +\pagestyle{chapter} +\part{Chapters} +\label{sec:org0129ee4} + +\chapter{Introduction} +\label{sec:org892f655} +\begin{enumerate} +\item Mechanism of Cavitation-Induced Material Degradation\hfill{}\textsc{ignore\_heading} +\label{sec:org132c6ad} +\end{enumerate} +\section{Cavitation\hfill{}\textsc{ignore}} +\label{sec:org411fa94} + +Stellites are a family of cobalt-base superalloys used in aggresive service environments due to retention of strength, wear resistance, and oxidation resistance at high temperature \cite{ahmedStructurePropertyRelationships2014, shinEffectMolybdenumMicrostructure2003}. First developed in the early 1900s \cite{hasanBasicsStellitesMachining2016}, stellites became critical to components used in medical implants \& tools, machine tools, and nuclear components, with new variations on the original CoCrWC and CoCrMoC alloys seeing expanding use in sectors like oil \& gas and chemical processing \cite{malayogluComparingPerformanceHIPed2003, ahmedStructurePropertyRelationships2014, raghuRecentDevelopmentsWear1997}. + + + +The main alloying elements in Stellite alloys are cobalt (Co), chromium (25-33 wt\% Cr), tungsten (0-18 wt\% W), molybdenum (0-18 wt\% Mo), carbon (0.1-3.3 wt\% C), and trace elements iron (Fe), nickel (Ni), silicon (Si), phosphorus (P), sulphur (S), boron (B), lanthanum (La), \& manganese (Mn); \tref{tab:stellite_composition} summarizes the nominal and measured composition of commonly used Stellite alloys \cite{ahmedMappingMechanicalProperties2023, alimardaniEffectLocalizedDynamic2010, ashworthMicrostructurePropertyRelationships1999, bunchCorrosionGallingResistant1989, davis2000nickel, desaiEffectCarbideSize1984, ferozhkhanMetallurgicalStudyStellite2017, pacquentinTemperatureInfluenceRepair2025, ratiaComparisonSlidingWear2019, zhangFrictionWearCharacterization2002}. Stellite alloys possess a composite-like microstructure, combining a cobalt-rich matrix strengthened by solid solutions of chromium, tungsten, \& molybdenum, with embedded hard carbide phases with carbide formers Cr (of carbide type \(\textrm{M}_{7}\textrm{C}_{3}\) \& \(\textrm{M}_{23}\textrm{C}_{6}\)) and W/Mo (of carbide type \(\textrm{MC}\) \& \(\textrm{M}_{6}\textrm{C}\)), that impede wear and crack propagation \cite{ahmedSlidingWearBlended2021a, crookCobaltbaseAlloysResist1994}. + +\afterpage{% +\begin{landscape} +\begin{ThreePartTable} + +%\renewcommand\TPTminimum{\pageheight} +%% Arrange for "longtable" to take up full width of text block +%\setlength\LTleft{0pt} +%\setlength\LTright{0pt} +%\setlength\tabcolsep{0pt} + +\begin{TableNotes} + \small + \item[a] Hot Isostatic Pressing + \item[b] Inductively coupled plasma atomic emission spectroscopy + \item[c] Shielded metal arc welding + \item[d] Gas tungsten Arc Welding + \item[e] Plasma transfered Arc Welding +\end{TableNotes} + +\caption{Stellite Compositions} +\label{tab:stellite_composition} + +\begin{longtable}{l|ll|ll|l|llllllll|lll} + +\toprule +\textbf{Alloy} & +\textbf{Co} & \textbf{Cr} & \textbf{W} & \textbf{Mo} & \textbf{C} & \textbf{Fe} & +\textbf{Ni} & \textbf{Si} & \textbf{P} & \textbf{S} & \textbf{B} & \textbf{La} & +\textbf{Mn} & \textbf{Ref} & \textbf{Process Type} & \textbf{Observation} \\ + + +\midrule +\multirow{4}{*}{Stellite 1} +& 47.7 & 30 & 13 & 0.5 & 2.5 & 3 & 1.5 & 1.3 & & & & & 0.5 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 48.6 & 33 & 12.5 & 0 & 2.5 & 1 & 1 & 1.3 & & & & & 0.1 & \cite{alimardaniEffectLocalizedDynamic2010} & & \\ +& 46.84 & 31.7 & 12.7 & 0.29 & 2.47 & 2.3 & 2.38 & 1.06 & & & & & 0.26 & \cite{ahmedMappingMechanicalProperties2023} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ + + +\midrule +\multirow{2}{*}{Stellite 3} +& 50.5 & 33 & 14 & & 2.5 & & & & & & & & & \cite{bunchCorrosionGallingResistant1989} & & \\ +& 49.24 & 29.57 & 12.07 & 0.67 & 2.52 & 2.32 & 1.07 & 1.79 & & & & & 0.75 & \cite{ratiaComparisonSlidingWear2019} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ + + +\midrule +\multirow{5}{*}{Stellite 4} +& 45.43 & 30 & 14 & 1 & 0.57 & 3 & 3 & 2 & & & & & 1 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 51.5 & 30 & 14 & & 1 & 1 & 2 & 0.5 & & & & & & \cite{zhangFrictionWearCharacterization2002} & & \\ +& 51.9 & 33 & 14 & & 1.1 & & & & & & & & & \cite{bunchCorrosionGallingResistant1989} & & \\ +& 49.41 & 31 & 14 & 0.12 & 0.67 & 2.16 & 1.82 & 1.04 & & & & & 0.26 & \cite{ahmedMappingMechanicalProperties2023} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ +& 50.2 & 29.8 & 14.4 & 0 & 0.7 & 1.9 & 1.9 & 0.8 & & & & & 0.3 & \cite{ashworthMicrostructurePropertyRelationships1999} & HIPed\tnote{a} & \\ + +\midrule +\multirow{10}{*}{Stellite 6} +& 51.5 & 28.5 & 4.5 & 1.5 & 1 & 5 & 3 & 2 & & & 1 & & 2 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 63.81 & 27.08 & 5.01 & & 0.96 & 0.73 & 0.87 & 1.47 & & & & & 0.07 & \cite{ratiaComparisonSlidingWear2019} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ +& 60.3 & 29 & 4.5 & & 1.2 & 2 & 2 & 1 & & & & & & \cite{zhangFrictionWearCharacterization2002} & & \\ +& 61.7 & 27.5 & 4.5 & 0.5 & 1.15 & 1.5 & 1.5 & 1.15 & & & & & 0.5 & \cite{bunchCorrosionGallingResistant1989} & & \\ +& 58.46 & 29.5 & 4.6 & 0.22 & 1.09 & 2.09 & 2.45 & 1.32 & & & & & 0.27 & \cite{ahmedMappingMechanicalProperties2023} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ +& 58.04 & 30.59 & 4.72 & & 1.24 & 2.03 & 1.87 & 0.80 & 0.01 & 0.01 & & & & \cite{ferozhkhanMetallurgicalStudyStellite2017} & PTAW\tnote{e} & OES \\ +& 55.95 & 27.85 & 3.29 & & 0.87 & 6.24 & 3.63 & 1.23 & 0.01 & 0.01 & & & 0.45 & \cite{ferozhkhanMetallurgicalStudyStellite2017} & GTAW\tnote{d} & OES \\ +& 52.40 & 30.37 & 3.57 & & 0.96 & 6.46 & 3.93 & 1.70 & 0.01 & 0.01 & & & 0.3 & \cite{ferozhkhanMetallurgicalStudyStellite2017} & SMAW\tnote{c} & OES \\ +& 60.3 & & 31.10 & 4.70 & 0.30 & 1.10 & 1.70 & 1.50 & 1.30 & & 0.00 & & 0.3 & \cite{pacquentinTemperatureInfluenceRepair2025} & LP-DED & ICP-AES \& GDMS \\ +& 60.6 & 27.7 & 5 & 0 & 1.2 & 1.9 & 2 & 1.3 & & & & & 0.3 & \cite{ashworthMicrostructurePropertyRelationships1999} & HIPed\tnote{a} & \\ + + +\midrule +\multirow{2}{*}{Stellite 12} +& 53.6 & 30 & 8.3 & & 1.4 & 3 & 1.5 & 0.7 & & & & & 1.5 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 55.22 & 29.65 & 8.15 & 0.2 & 1.49 & 2.07 & 2.04 & 0.91 & & & & & 0.27 & \cite{ahmedMappingMechanicalProperties2023} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ + + +\midrule +\multirow{2}{*}{Stellite 20} +& 41.05 & 33 & 17.5 & & 2.45 & 2.5 & 2.5 & & & & & & 1 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 43.19 & 31.85 & 16.3 & 0.27 & 2.35 & 2.5 & 2.28 & 1 & & & & & 0.26 & \cite{ahmedMappingMechanicalProperties2023} & HIPed\tnote{a} & ICP-OES\tnote{b} \\ + + +\midrule +\multirow{2}{*}{Stellite 21} +& 59.493 & 27 & & 5.5 & 0.25 & 3 & 2.75 & 1 & & & 0.007 & & 1 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 60.6 & 26.9 & 0 & 5.7 & 0.2 & 1.3 & 2.7 & 1.9 & & & & & 0.7 & \cite{ashworthMicrostructurePropertyRelationships1999} & HIPed\tnote{a} & \\ + + +\midrule +\multirow{2}{*}{Stellite 31} +& 57.5 & 22 & 7.5 & & 0.5 & 1.5 & 10 & 0.5 & & & & & 0.5 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 52.9 & 25.3 & 7.8 & 0 & 0.5 & 1.1 & 11.4 & 0.6 & & & & & 0.4 & \cite{ashworthMicrostructurePropertyRelationships1999} & HIPed\tnote{a} & \\ + + +\midrule +\multirow{2}{*}{Stellite 190} +& 46.7 & 27 & 14 & 1 & 3.3 & 3 & 3 & 1 & & & & & 1 & \cite{davis2000nickel} & \multicolumn{2}{c}{Nominal composition} \\ +& 48.72 & 27.25 & 14.4 & 0.2 & 3.21 & 2.1 & 2.81 & 1 & & & & & 0.31 & \cite{ahmedMappingMechanicalProperties2023} +& HIPed\tnote{a} & ICP-OES\tnote{b} \\ + + +\end{longtable} +\end{ThreePartTable} +\end{landscape} +} + + +Understanding the cobalt phase is crucial for studying structural changes in Co-based alloys widely used in industry. The fcc cobalt phase, especially its delayed transition to hcp at ambient and moderate temperatures \cite{DUBOS2020128812}, is of particular interest due to its impact on material properties in Co-based alloys \cite{Rajan19821161}. As the cobalt phase in stellite alloys is observed to consist of the fcc phase \cite{Rajan19821161}, the potential for strain-induced fcc to hcp transformation is of interest under the mechanical loading of cavitation erosion. + + +Cobalt exhibits a hexagonal close-packed (hcp) structure above 700 K \footnote\{the theoretical transition temperature was determined to be 825 K by Lizarraga et al \cite{Lizarraga2017}\} and shifts to a face-centered cubic (fcc) structure above this temperature. + + +At ambient conditions, the metastable FCC retained phase can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}. + +The main allotropes of the Co solid solution in stellite are the hexagonal close-packed (hcp) \(\epsilon−Co\) (ICDD\# 01-071-4239) and the face-centered cubic (fcc) \(\gamma−Co\) (ICDD 00-015-0806) \cite{wuMicrostructureEvolutionCrack2019} with the \(\epsilon−Co\) phase being more thermodynamically stable below 700K \cite{lizarragaFirstPrinciplesTheory2017}. However the \$\(\gamma\)\$\textrightarrow\(\epsilon\) transformation is difficult to achieve under normal condition, leading to cobalt alloys often retaining the metastable \(\gamma\) phase \cite{davis2000nickel, frenkMicrostructuralEffectsSliding1994}. At ambient conditions, the metastable fcc retained phase in stellites can undergo a strain-induced martensitic-type transition involving partial dislocation movement \cite{HUANG2023106170}, such as during cavitation erosion as observed experimentally by Woodford \cite{woodfordCavitationerosionlnducedPhaseTransformations1972}. + +The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) of cobalt \cite{Tawancy1986337} + + +This promotes the FCC→HCP martensitic transformation and improves the mechanical properties of the alloy. Phase composition seriously affects the properties of alloys. The FCC phase is soft and plastic, while the HCP phase is hard and not plastic. Therefore, when an alloy undergoes strain-induced FCC→HCP martensitic transformation, the martensite HCP phase plays a “secondary hardening” effect, which greatly improves the overall hardness of the alloy. + + + + +This fcc to hcp transition is linked to the very low stacking fault energy of the fcc structure (approximately 7 mJ/m²). The addition of other elements influences these characteristics: solid-solution strengthening increases the fcc cobalt matrix strength by distorting the atomic lattice and can decrease the low stacking fault energy by adjusting the electronic structure. Solute atoms like molybdenum (Mo) and tungsten (W), due to their large atomic sizes, discourage dislocation motion in stellites. Since dislocation cross-slip is a primary deformation mode in imperfect crystals at elevated temperatures and dislocation slip is a diffusion-enhanced process at high temperatures, this contributes to high-temperature stability. Furthermore, elements like nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W) tend to stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm). + + + +The \(\epsilon-\textrm{Co}\) (ICDD\# 01-071-4239)and \(\gamma-\textrm{Co}\) (ICDD 00-015-0806) phases are the main phases of the Co solid solution in stellite +Although the \(\epsilon-\textrm{Co}\) phase is more stable at room temperature according to the phase diagram, cobalt alloys often posses a majority \(\gamma-\textrm{Co}\) phase; the \$\(\gamma\)\$\textrightarrow\(\epsilon\) transformation rarely occurs under normal cooling condiyions and the metastable \(\gamma\) phase is generally retained + + + +Cobalt and Co-Cr alloys undergo thermally induced phase transformation from the high temperature face-centered cubic (fcc) \(\gamma\) phase to low temperature hexagonal close-packed (hcp) \(\epsilon\) phase at 700 K and strain induced fcc-hcp transition through maretensitic-type mechanism (partial movement of dislocations) \cite{HUANG2023106170}. At ambient conditions, the metastable FCC retained phase in stellites can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}; the metastable fcc cobalt phase in stellite alloys \cite{Rajan19821161} absorbs a large part of imparted energy under the mechanical loading of cavitation erosion. The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) \cite{Tawancy1986337}. + +Solid-solution strengthening leads to increase of the fcc cobalt matrix strength (due to distortion of the atomic lattice with the addition of elements of different atomic radii), and decrease of low stacking fault energy \cite{Tawancy1986337} due to the adjusted electronic structure of the metallic lattice. Dislocation motion in stellites is discouraged by solute atoms of Mo and W, due to the large atomic sizes. Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. In addition, nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W), stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm) \cite{Vacchieri20171100, Tawancy1986337}. + + + +\cite{woodfordCavitationerosionlnducedPhaseTransformations1972} + +confirmed that \$\(\gamma\)\$\textrightarrow\(\epsilon\) transformation occur on the surface of cobalt-base alloys during cavitation erosion, a relationship a direct relationship between . While the extent of this deformation-induced transformation was observed to increase with the severity of erosion and reach a steady state corresponding with the weight loss rate, subsequent experiments on Stellite 6B with varying initial hcp phase content and different aging treatments failed to establish a direct correlation between the transformation characteristics and erosion resistance. + + + +Solid-solution strengthening is provided by elements not tied in secondary phases, leading to increase of the fcc cobalt matrix strength. + +With the addition of elements with different atomic radiuses, the atomic lattice of the fcc cobalt matrix is distorted leading to increased strength. The already low stacking fault energy of the fcc cobalt structure (7 mJ/m2) \cite{Tawancy1986337} is further decreased, inhibiting dislocation cross slip. +Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. + +The addition of nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt, while chromium (Cr) and tungsten (W), stabilize the hcp structure. Cr guarantees hot corrosion resistance and forms M23C6 carbides, while form MC carbides \cite{Vacchieri20171100}. The fcc cobalt phase has lattice constant a = 0.35 nm while the hcp cobalt phase has lattice constant a = 0.25 nm and c = 0.41 nm \cite{Tawancy1986337}. +\begin{enumerate} +\item Paragraph: Other Elements\hfill{}\textsc{ignore} +\label{sec:org5cbf8d1} + +In Co based superalloys, Ni element is added in order to stabilize the fcc crystalline structure from room temperature to the melting temperature. It is also known that Fe also stabilises the fcc structure like Ni [24]. According to images of the elemental mapping analysis of Ni and Fe, they exhibited a homogenous distribution within the matrix. + +In the elemental mapping analysis, the amount of oxygen element increased significantly in the precipitates stated as M23C6 type carbides. It was reported that M7C3 and MC type carbides preferentially oxidized when exposed to high temperature [37]. Similarly, it was understood in the present study that M23C6 type carbides also oxidized during the sintering process. + + +The proportion and type of carbides depend on carbon content and the relative amounts of carbon with carbide formers (Cr, W, Mo), which greatly influence alloy performance and intended applications as carbides provide higher strength and but may reduce corrosion resistance due to localized corrosion at carbide boundaries. High carbon alloy (>1.2 wt\%) have higher hardness due to greater carbide formation and are primarily used for wear resistance, low carbon alloys (<0.5 wt\%) are used for enhanced corrosion resistance, and medium carbon alloys (0.5 wt\% - 1.2 wt\%) are used in applications requiring a combination of wear and corrosion resistance \cite{davis2000nickel}. + +The carbide and grain size can be controlled by the rate of freezing, with larger carbide sizes indicating slower freezing rates \cite{yuInfluenceManufacturingProcess2008}. + + +The strength of most cobalt base superalloys is derived from the carbide phases present in the matrix and distributed around the grain boundaries. The carbides that form depend on the composition and thermal history of the material. The carbide former elements are from group IV (Ti, Zr, Hf), group V (Cb, Ta), and group VI (Cr, Mo, W). The types of carbides that are formed are as follows (M and C represents metal and carbon atoms respectively): + +The types of chromium carbides formed, in order of increasing Cr/C ratio, are: + + +\begin{center} +\begin{tabular}{lll} +\(M_{3}C_{2}\) & \#04-004-4541 & \cite{dingStudyCarbidePrecipitation2021}\\ +\end{tabular} +\end{center} + + +\begin{center} +\begin{tabular}{lll} +Phase & \(Cr_{3}C_{2}\) & \(Cr_{23}C_{6}\)\\ +ICDD & \#04-004-4541 & \\ +Crystal system & Orthorhombic & Cubic\\ +Space group & Pnam (62) & Fm3m (225)\\ +Pearson symbol & oP2O & cF116\\ +CAS & 12012-05-0 & 12105-81-6\\ +\end{tabular} +\end{center} + +\cite{morrisStandardXrayDiffraction} + + +M 7 C3 : trigonal, a high chromium content carbide which forms at a slightly higher Cr/C ratio; +M 23 C6 : cubic, a high chromium content carbide which forms at an higher Cr/C ratio, when the Cr is greater than 5 wt\% of the alloy; + +M6 C: complex cubic, a carbide phase whose volume fraction increases as refractory metals are introduced; +MC: fcc NaCl structure, a carbide comprising metal groups IV and VI. + +These carbides are listed above in the order of increasing stability, or free energy of formation. The stronger the carbide formers used, the greater is the tendency to form M6 C and MC carbides. The type of carbides that form is dependent upon both thermal history and composition. +\item Chromium carbide +\label{sec:org3780a2a} + +\begin{table}[htbp] +\caption{Cr3C2} +\centering +\begin{tabular}{rrrrrr} +d(A) & Irel & h & k & l & 2\(\theta\)\\ +\hline +4.978 & 1L & 1 & 1 & 0 & 17.804\\ +3.983 & 1L & 1 & 2 & 0 & 22.302\\ +3.146 & 2 & 1 & 3 & 0 & 28.343\\ +2.7460 & 18 & 0 & 1 & 1 & 32.582\\ +2.5478 & 23 & 1 & 4 & 0 & 35.196\\ +2.4897 & 13 & 2 & 2 & 0 & 36.045\\ +2.4596 & 9 & 1 & 1 & 1 & 36.502\\ +2.3063 & 100 & 1 & 2 & 1 & 39.023\\ +2.2751 & 10 & 0 & 3 & 1 & 39.580\\ +2.2409 & 60 & 2 & 3 & 0 & 40.210\\ +2.1215 & 21 & 1 & 5 & 0 & 42.580\\ +2.1036 & 10 & 1 & 3 & 1 & 42 .961\\ +1.9912 & 25 & 2 & 4 & 0 & 45.518\\ +1.9481 & 45 & 2 & 1 & 1 & 46.582\\ +1.9151 & 29 & 0 & 6 & 0 & 47.434\\ +1.8934 & 34 & 1 & 4 & 1 & 48.011\\ +1.8691 & 49 & 2 & 2 & 1 & 48.676\\ +1.8190 & 27 & 3 & 1 & 0 & 50.107\\ +1.7833 & 26 & 0 & 5 & 1 & 51.182\\ +1.7670 & 1 & 2 & 5 & 0 & 51.691\\ +1.7567 & 8 & 2 & 3 & 1 & 52.016\\ +1.6975 & 25 & 1 & 5 & 1 & 53.972\\ +1.6602 & 3 & 3 & 3 & 0 & 55.289\\ +1.6285 & 6 & 2 & 4 & 1 & 56.458\\ +1.5734 & 5 & 1 & 7 & 0+ & 58.625\\ +1.5302 & 9 & 3 & 1 & 1 & 60.450\\ +1.4987 & 7 & 2 & 5 & 1 & 61.858\\ +1.4375 & 3 & 3 & 5 & 0 & 54.803\\ +1.4192 & 3 & 0 & 7 & 1 & 65.742\\ +1.4143 & 19 & 0 & 0 & 2 & 66.004\\ +1.3902 & 1 & 1 & 8 & 0 & 67.298\\ +1.3720 & 5 & 4 & 1 & 0 & 68.313\\ +1.3273 & 4 & 3 & 6 & 0 & 70.951\\ +1.2998 & 1 & 4 & 3 & 0 & 72.691\\ +1.2812 & 2 & 3 & 5 & 1 & 73.916\\ +1.2626 & 5 & 2 & 7 & 1 & 75.192\\ +1.2474 & 13 & 1 & 8 & 1 & 76.268\\ +1.2367 & 5 & 1 & 4 & 2 & 77.054\\ +1.2342 & 6 & 4 & 1 & 1 & 77.234\\ +1.2296 & 3 & 2 & 2 & 2 & 77.581\\ +1.2254 & 8 & 3 & 7 & 0 & 77.896\\ +1.2135 & 6 & 4 & 2 & 1 & 78.806\\ +1.2017 & 11 & 3 & 6 & 1 & 79.731\\ +1.1961 & 12 & 2 & 3 & 2 & 80.184\\ +1.1810 & 10 & 4 & 3 & 1 & 81.421\\ +1.1768 & 6 & 1 & 5 & 2 & 81.778\\ +1.1619 & 6 & 2 & 8 & 1 & 83.056\\ +1.1590 & 6 & 2 & 9 & 0 & 83.303\\ +1.1531 & 8 & 2 & 4 & 2 & 83.832\\ +1.1397 & 4 & 4 & 4 & 1 & 85.042\\ +1.1377 & 11 & 0 & 6 & 2 & 85.225\\ +1.1247 & 8 & 1 & 10 & 0+ & 86.451\\ +1.1167 & 9 & 3 & 1 & 2 & 87.226\\ +1.1005 & 4 & 5 & 1 & 0 & 88.851\\ +1.0923 & 4 & 4 & 5 & 1 & 89.693\\ +1.0856 & 1 & 5 & 2 & 0 & 90.395\\ +1.0767 & 2 & 3 & 3 & 2 & 91.354\\ +1.0722 & 1 & 2 & 9 & 1 & 91.815\\ +1.06085 & 3 & 2 & 10 & 0 & 93.123\\ +1.05708 & 3 & 4 & 7 & 0 & 93.556\\ +1.05190 & 3 & 2 & 6 & 2+ & 91.158\\ +1.01926 & 3 & 3 & 9 & 0 & 91.168\\ +1.03173 & 3 & 5 & 4 & 0 & 96.595\\ +1.02616 & 2 & 1 & 11 & 0 & 97.295\\ +1.01339 & 2 & 5 & 2 & 1 & 98.950\\ +\end{tabular} +\end{table} +\item Paragraph: Tungsten and Molybdenum carbides +\label{sec:org2d42c92} + +Tungsten (W) and molybdenum (Mo) are refractory elements that provide solid solution strengthening to the matrix, by virtue of their large atomic size that impedes dislocation flow when present as solute atoms \cite{boeckRelationshipsProcessingMicrostructure1985}, and also form \(\textrm{M}_6\textrm{C}\) and \(\textrm{M}_12\textrm{C}\) carbides along with \(\textrm{MC}\) carbides and \(\textrm{Co}_3\textrm{M}\) \& \(\textrm{Co}_7\textrm{M}_6\) intermetallics during solidification. + +In carbon-rich regions, the \(\textrm{MC}\) phase (of type \(\textrm{WC}\) and \(\textrm{MoC}\)) is observed \cite{zhangThermodynamicInvestigationPhase2019}, which ca + + +In carbon-poor regions, ternary \(\textrm{M}_6\textrm{C}\) and \(\textrm{M}_{12}\textrm{C}\) carbides have been identified, where the \(\textrm{M}_6\textrm{C}\) carbide (of type \(\textrm{Co}_3\textrm{Mo}_3\textrm{C}\)) is stable in the temperature ranges of 900C to 1300C and can vary in composition from Mo\textsubscript{40}\textsubscript{Co}\textsubscript{46C}\textsubscript{14} to Mo56Co30C14, while the \(Mo_12C\) carbide of type (\(Co6Mo6C\) carbide decomposes into \(Mo_6C\) and \(\mu-Mo\) phases above 1100C \cite{zhangThermodynamicModelingCCoMo2016}. + +When present in large quantities, W and Mo also participate in formation of W-rich or Mo-rich carbides during alloy solidification \cite{davis2000nickel, raghuRecentDevelopmentsWear1997}, + +leading to generation of Topologically Close-Packed (TCP) phases, such as the \(\mu\) phase (of type Co\textsubscript{7W6} and Co7Mo6) and \(\sigma\) phase (pf type Co3W and Co3Mo) \cite{zhangThermodynamicInvestigationPhase2019}, which are intermetallic brittle phases that add strength to the material \cite{yuTriboMechanicalEvaluationsCobaltBased2007, ishidaIntermetallicCompoundsCobase2008} while also promoting crack initiation and propagation \cite{zhaoFirstprinciplesStudyPreferential2023}. Previous work on the Stellite 1 sample by Ahmed et al \cite{ahmedMappingMechanicalProperties2023} indicate that Co6W6C is identified as the main W-rich carbide in Stellite 1, although Co3W3C was also identified inaddition to Co3W and Co7W intermetallics. + + + + +There are two main phases in the tungsten-carbon system: the hexagonal monocarbide \(\textrm{WC}\) (ICDD Card\# 03-065-4539, COD:2102265), denoted as \(\delta-\textrm{WC}\), and multiple variations of hexagonal-close-packed subcarbide \(\textrm{W}_2\textrm{C}\) (ICDD:00-002-1134, COD:1539792) \cite{kurlovPhaseEquilibriaWC2006, tulhoffCarbides2000} + +WC carbides precipitate as discrete particles distributed heterogeneously throughout the alloy intragranularly + +The precipitation of the tungsten-rich phase \(M_6C\) is closely related to the decomposition of the MC carbide, and the \(M_6C\) only occurs in the vicinity of the MC \cite{jiangSecondaryM6CPrecipitation1999}, as \(M_6C\) carbides form only when the tungsten and.or molybdenum content exceeds 4-6 a/o. + + + + + +Plasma nitrided Stellite 6 and 12 were found to have lowered corrosion resistance due to the consumption of chromium in CrN precipitates and lack of chromium oxide as protective layer \cite{poshtahaniPlasmaNitridingEffect2023}. + + + +The predominant carbide found in high-carbon Stellite is chromium rich Cr7C3 type whereas carbides such as Cr6C and Cr23C6 are found in low-carbon Stellite. These carbides have a very high hardness (i.e. more than 1000 HV) and are responsible for imparting hardness to coating of Stellite thus improving its sliding wear resistance. + + + + +Chromium carbides have high hardness and wear resistance, as well as excellent resistance to chemical corrosion, making them often used in surface coatings \cite{liElectronicMechanicalProperties2011} + +In the Cr-C binary phase diagram, there are three phases : cubic Cr23C6 (space group , melting point 1848 K), orthorhombic Cr3C2 (space group Pnma, melting point 2083 K) and Cr7C3 (space group Pnma, melting point 2038 K) \cite{medvedevaStabilityBinaryTernary2015} \cite{liElectronicMechanicalProperties2011} + +The M\textsubscript{23C6} carbides are formed during heat treatment of carbides with a lower M/C ratio or from solid solution close to boundaries \cite{medvedevaStabilityBinaryTernary2015}. Fine M23C6 carbides act as obstacles to gliding of mobile dislocations, which result in long-term creep strength \cite{godecCoarseningBehaviourM23C62016}. + +Although M23C6 can precipitate as primary carbide during solidification, it is most commonly found in secondary carbides along grain boundaries. + +M7C3 is a metastable pseudo-eutectic carbide that typically forms at lower carbon-chromium ratios and effectively transforms into secondary M23C6 upon heat treatment. + +In addition to being a carbide former, chromium provides solid solution strengthing and corrosion/oxidation resistance to the cobalt-based matrix. + + +The Cr7C3 carbide is unstable at high temperatures and transforms to M\textsubscript{23}C\textsubscript{6} upon heat treatment. Under further temperature and time, Cr\textsubscript{23}C\textsubscript{6} partially transforms to Cr\textsubscript{6C} \cite{mohammadnezhadInsightMicrostructureCharacterization}. + +$$ 2Cr_{7}C_{3} + 9Cr \rightarrow Cr_{23}C_{6} $$ +$$ Cr_{23}C_{6} + 13Cr \rightarrow 6Cr_{6}C $$ + +$$ 23Cr_{7}C_{3} \rightarrow 7Cr_{23}C_6 + 27C $$ +$$ 6C + 23Cr \rightarrow Cr23C6 $$ + + + + +The manufacturing process dictates the microstructure of Stellite alloys, with powder metallurgy and additive manufacturing surpass conventional casting and welding. Traditional casting involves slow cooling rates that produce coarse, dendritic microstructures characterized by elemental segregation and a continuous, interdendritic network of carbides. + +Welding Stellite alloys onto a substrate creates as-cast microstructure and a fusion zone, where the diffusion of elements alters alloy composition with detrimental phase transformations such as brittle intermetallic compounds \cite{wong-kianComparisonErosioncorrosionBehaviour}. + +In contrast, thermal spray processes and powder metallurgy (HIPing) produce microstructure that largely retain the originating powder's original microstructure, with thermal spray producing a layered carbide-free microstructure incorporating splats, oxides, \& porosity, while HIPing yields a dense, porosity-free and highly homogeneous microstructure with small spherical carbides which impede crack propagation, improving fatigue resistance. + +The absense of solidification from a liquid phase prevents element segregation associated with as-cast and as-welded microstructures. \cite{wong-kianComparisonErosioncorrosionBehaviour} + +The difficulty with processing make Stellite alloys ideal for powder processing using net shaping techniques. + +\cite{ashworthMicrostructurePropertyRelationships1999} + + +Further processing via re-HIPing can induce carbide precipitation, carbide coarsening and additional solid-solution strengthening of the matrix, improving wear performance. Temperatures above 1000C are typically required to ensure homogenisation of the microstructure and reduction in porosity \cite{houdkovaEffectHeatTreatment2016}. + + +Recently developed additive manufacturing techniques such as Selective Laser Melting (SLM) and Powder Bed Fusion (PBF) leverage rapid solidification to create fine-grained columnar microstructure. + + + +Ashworth et al \cite{ashworthMicrostructurePropertyRelationships1999} found that high carbon Stellite alloys benefitted from higher hipping temperatures (1200 C) while low carbon Stellite alloys reached optimum properties at a HIPing temperature of 1120 C. + +Beyond the process, alloy composition is crucial; high-carbon Stellite alloys exhibit superior wear resistance due to a much larger volume fraction of hard carbides, while the substitution of tungsten with molybdenum can further enhance erosion-corrosion resistance by modifying the carbide types and strengthening the matrix [7586, 7788, 7992, 3927, 3928, 4080, 4081, 4082]. + +Yu et al \cite{yuInfluenceManufacturingProcess2008} found that HIPed stellite 6 had lower fatigue performance to HIPed stellite 20. + +Rehan et al \cite{ahmedInfluenceReHIPingStructure2013} + +Wong Kian et al \cite{wong-kianComparisonErosioncorrosionBehaviour} found that HIPed versions of Stellite 1, 6 and 12 consistently showed superior resistance to as-weld overlays in erosion–corrosion tests using a rotating slurry pot configuration. + +Stellite 4 \cite{yuTriboMechanicalEvaluationsCobaltBased2007} +Stellite 20 \cite{yuComparisonTriboMechanicalProperties2007} +Stellite 6 \cite{yuInfluenceManufacturingProcess2008} + +\begin{center} +\begin{tabular}{llrrrrrrrr} + & Co & Cr & W & C & Mo & Fe & Ni & Mn & Si\\ +\hline +Cast Stellite 4 & Bal. & 31.7 & 13.5 & 0.90 & 0.20 & 1.65 & 0.65 & 0.56 & 0.72\\ +HIPed Stellite 4 & Bal. & 31.0 & 14.4 & 0.67 & 0.12 & 2.16 & 1.82 & 0.26 & 1.04\\ +\hline +Cast Stellite 20 & Bal. & 34.50 & 16.50 & 2.39 & 0.50 & 1.50 & 1.00 & 0.60 & 0.78\\ +HIPed Stellite 20 & Bal. & 31.85 & 16.30 & 2.35 & 0.27 & 2.50 & 2.28 & 0.26 & 1.00\\ +\hline +Cast Stellite 6 alloy & Bal. & 27.10 & 4.95 & 0.95 & 0.30 & 1.10 & 0.60 & 0.90 & 1.24\\ +HIPed Stellite 6 alloy & Bal. & 29.50 & 4.60 & 1.09 & 0.22 & 2.09 & 2.45 & 0.27 & 1.32\\ +\end{tabular} +\end{center} + + + + + + + +As well as the corrosion behaviour being of interest, Malayoglu and Neville [16] conducted a comparative study on the erosion-corrosion performance of both HIPed and investment cast Stellite 6® in 3.5\% NaCl solution as a function of temperature and the level of erosive particle loading. They found that in all cases, the HIPed Stellite 6® exhibited the higher erosioncorrosion resistance, which they attributed to the fact that the carbides are not interconnected in the HIPed material whereas eutectic and dendritic carbides in the cast structure form a network of interconnected material. Furthermore, the mean free path between carbides is much smaller in the HIPed material and as such the material responded homogenously to 4 erosion-corrosion. Another study comparing the erosion-corrosion behaviour of a range of HIPed and weld-deposited Stellite alloys in a nitric acid environment demonstrated that the HIPed alloys generally exhibited a lower mass loss which was again attributed to the finer microstructure [17]. +A similar conclusion was also reached by Neville and Malayoglu [18] who attributed the superior corrosion resistance of HIPed Stellite 6 to its microstructure with equiaxed carbides and an absence of areas of chromium-depleted matrix material, due to reduced segregation. + + + +Corrosion performance studies have demonstrated the superiority of HIPed materials. + +Malayoglu and Neville evaluated HIPed versus as-cast Stellite 6 in 3.5\% NaCl solution under varying temperature and erosive particle loading conditions, with their findings of superior erosion-corrosion resistance in HIPed materials at temperatures up to 90C attributed to homogeneous material response. + +Additional investigations in nitric acid environments confirmed reduced mass loss in HIPed alloys [17], with enhanced corrosion resistance attributed to equiaxed carbides and absence of chromium-depleted matrix regions due to reduced segregation [18]. + + +Pitting corrosion + +Chromium-rich carbides (M3C2, M7C3) M23C6) and refractory-element-rich carbides (M6C and MC). + + +The susceptibility of passivating metals to loccalized corrosion is dependent on the passive film's physical and chemical structure and ability to resist breakdown and to repassivate once corrosion has initiated. + +Malayoglu and Neville \cite{malayogluCharacterisationPassiveFilm2005} find that Stellite 6 shows a multilayer passive film, where the outer surface consists primarily of Cr(OH)3 / Cr2O3 and WO2 , and the inner layer consists of Cr(OH)3 / Cr2O3, metallic Cr \& W, and WO3, with no evidence of Cl- ion content, unlike that reported for stainless steels. + + + + +Wong-Kian et al.16 showed that under erosion-corrosion conditions HIPed Stellite alloys 1, 6, and 21 had lower mass loss than the welded specimens of the same Stellites. They related their finding to the finer and homogeneous microstructure, which was obtained after HIPing. They also showed that wear resistance of the cobalt-based alloys is promoted by the harder complex carbides of chromium and tungsten, while corrosion resistance is enhanced by the presence of cobalt in the matrix. +\end{enumerate} +\section{Comparison to Literature} +\label{sec:org6bdc5a4} +General Microstructure of Cast Alloys + +Stellite 4: Features a hypoeutectic microstructure consisting of Co-rich dendrites, a Cr-rich eutectic phase, and W-rich carbides. +Stellite 6: Also has a hypoeutectic microstructure with Co-rich dendrites set in a lamellar eutectic of Cr-rich and W-rich carbides. The relatively large carbides suggest a slow cooling rate during casting. +Stellite 20: Possesses a hypereutectic microstructure, characterized by large, primary blocky (idiomorphic) Cr-rich carbides surrounded by a dendritic CoCrW solid solution and eutectic phases. + + +The remarkable ability of Stellite alloys to withstand these specific challenges stems from key metallurgical features. Their corrosion resistance is primarily attributed to a high chromium content, typically 20-30 wt.\%, which promotes the formation of a highly stable, tenacious, and self-healing chromium-rich passive oxide film on the material's surface; this film acts as a barrier isolating the underlying alloy from the corrosive environment. Alloying elements such as molybdenum and tungsten can further enhance this passivity, particularly improving resistance to localized corrosion phenomena like pitting and crevice corrosion in aggressive media. Concurrently, their outstanding cavitation resistance is largely derived from the unique behavior of the cobalt-rich matrix, which can undergo a stress-induced crystallographic transformation from a face-centered cubic (fcc) to a hexagonal close-packed (hcp) structure. This transformation, often facilitated by mechanical twinning, effectively absorbs the intense, localized impact energy from collapsing cavitation bubbles and leads to significant work hardening, thereby impeding material detachment and erosion. + +Antony suggests that the cavitation-erosion resistance of Stellites derives from the matrix phase and is enhanced by the strain-induced fcc \textrightarrow hcp allotropic transformation \cite{antonyWearResistantCobaltBaseAlloys1983}. + + + + + +The cavitation erosion of stellites has been investigated in experimental studies \cite{Wang2023, Szala2022741, Mitelea2022967, Liu2022, Sun2021, Szala2021, Zhang2021, Mutascu2019776, Kovalenko2019175, E201890, Ciubotariu2016154, Singh201487, Hattor2014257, Depczynski20131045, Singh2012498, Romo201216, Hattori20091954, Ding201797, Guo2016123, Ciubotariu201698}, along with investigations into cobalt-based alloys \cite{Lavigne2022, Hou2020, Liu2019, Zhang20191060, E2019246, Romero2019581, Romero2019518, Lei20119, Qin2011209, Ding200866, Feng2006558}. + + + +Stellites achieve oxidation resistance through the formation of a passivating external Cr2O3 scale, due to the high proportion of Cr in their chemical composition \cite{pettitOxidationHotCorrosion1984}. + +as seen by Zhang et al in Green Death solution \cite{zhangPittingCorrosionCharacterization2014}. + +However, Cr-based carbides may be preferentialy oxidized below the external Cr2O3 scale, particularly at the boundary of carbides which are depleted of Cr \cite{zhangPittingCorrosionCharacterization2014}, where preferential attack of carbides proceed until they have been consumed \cite{pettitOxidationHotCorrosion1984}. + + + +Mohamed et al find that Stellite exposed to cyclic potentiodynamic polarization in 3\% NaCl solution results in slight depletion of Co, accompanies with corresponding enrichment in Cr and W \cite{mohamedLocalizedCorrosionBehaviour1999}. + +Mohamed + + + +Lemaire et al \cite{lemaireEvidenceTribocorrosionWear2001} investigated the behavior of Stellite 6 in pressurized high temperature water and proposed an oxidative wear mechanism where wear proceeds by repeated detachment of the surface oxide spontaneously forming on the stellite surface. + +Di Martino et al \cite{dimartinoCorrosionMetalsAlloys2004} also found that the protective chromium-rich film are abraded easily, leading to further corrosion. + + +In such lower-temperature regimes, the passive films formed are typically very thin (in the nanometer range, rather than the micrometer scale observed at high temperatures) + + +It is also known for passive alloys that there is generally an inverse relationship between the thickness of the film and its protective property. This was seen in work by Malayoglu et al.3 where the breakdown potential in anodic polarization tests was shown to be reduced aligned with a thinning of the passive film detected by XPS on HIPed Stellite 6 in 3.5\% NaCl \cite{neville306AqueousCorrosion2010}. + +Molybdenum and tungsten have favorable effects on the selective oxidation of chromium until chromium has been depleted, at which point molybdenum and tungsten result in increased oxidation due to development of less protective phases \cite{pettitOxidationHotCorrosion1984}. +\chapter{Materials and Experimental Test Procedure} +\label{sec:org224086f} + +The cast Stellite 1 alloys were produced via sand castings. Spherical gas-atomized Stellite 1 powders were used to produce HIPed samples through consolidation in a HIPing vessel at a temperature of 1200C and 100 MPa for 4 hours, as reported in previous work by Ahmed et al \cite{ahmedInfluenceAlloyComposition2025}. Sieve analysis of the gas-atomized powders indicate that powder particles were in the size range of 45 to 180 um \cite{ahmedInfluenceAlloyComposition2025}, with SEM analysis conducted to measure particle size via image analysis. + +\begin{center} +\begin{tabular}{lrrrrr} + & +250 & +180 & +125 & +45 & -45\\ +HIPed Stellite 1 & 0.10 & 2.40 & 47.90 & 49.50 & 0.10\\ +\end{tabular} +\end{center} + + + +The microstructure of the alloys were observed via scanning electron microscopy (SEM) using a back-scattered electron imaging detector (BSE), with elemental compositions of the observed phases determined via energy dispersive X-ray spectroscopy (EDS). Image analysis of BSE images was conducted to ascertain area fractions of individual phases. + + +Microstructure phase analysis was performed with a Bruker Discover D8 <> X-ray diffractometer (XRD) with Cu \(K_{\alpha}\) radiation (\(\lambda = 1.5406 \AA\)) in Bragg-Brentano \(\theta:2\theta\) configuration across the diffraction angle range 20deg <> to 120deg <> with a step size of 0.00deg <>. + +The volume fraction of \(\epsilon\)-Co is calculated via the relative intensity of the \((200)_{\gamma}\) and \((10\bar{1}1)_{hcp}\) peaks, as proposed by Sage and Guillaud \cite{sageMethodeDanalyseQuantitative1950}. + +\begin{equation} +\textrm{hcp} (\textrm{vol}\%) = \frac{I(10\bar{1}1)_{\epsilon}}{I(10\bar{1}1)_{\epsilon} + 1.5I(200)_{\gamma}} +\end{equation} + + + + +The Vickers microhardness was measured using a Wilson hardness tester under loads of BLAH. Thirty measurements under each load were conducted on each sample. +\section{Experimental determination of SFE} +\label{sec:org7f9731a} + +To experimentally determine the SFE, the XRD method proposed by Reed and Schramm was employed \cite{reedRelationshipStackingfaultEnergy1974}: + +\begin{equation} +SFE = \frac{K_{111} \omega_0 G_{111} a_0}{\pi \sqrt{3}} \frac{{<\epsilon_{50\AA}^2>}_{111}}{\alpha} A^{-0.37} +\end{equation} + +where: + + +\begin{equation} +K_{111}\omega_0 &= 6.6 \\ +G_{111} = \frac{1}{3}\frac{1}{C_{44} + C_{11} - C_{12}} +A &= \frac{1 C_{44}}{C_{11}-C_{12}} +\end{equation} + + +ployed \cite{reedRelationshipStackingfaultEnergy1974}: + +\(SFE\) = stacking fault energy \(\frac{mJ}{m^2}\) +\(K_{111}\omega_0\) = 6.6, as obtained by +\(A\) is the Zener elastic anisotropy +\(C_{ij}\) are elastic stiffness coefficients +\(G_{111}\) is the shear modulus of the (111)-plane, in which stacking faults are formed +\(a_0\) is the lattic constant of the fcc-metal matrix +\({<\epsilon^2_{111}>}_{50\AA}\) is thr root mean square microstrain in the <111> direction averaged over the distance of \(50 \AA\) +\(\alpha\) is stacking fault probability +\begin{enumerate} +\item Elastic constant +\label{sec:orga114ba1} + + + + + +Microhardness measurements were taken on the surfaces of the as-cast and HIPed samples. The Wilson Tukon 1102 hardness tester was used for Vickers microhardness testing with a load of 300 grams (HV\textsubscript{0.3}) for 10s, and averaged by using ten individual indentations. The specimen surface was prepared in the same fashion as for microstructural analysis. + +Previous work + + +The indentation fracture toughness was made with hardness equipment (AVK-A, AKASHI) at a load of 49 N for 10 s, and the value was obtained from five measurements on the cross section. The fracture toughness was evaluated based to the Evans-Wilshaw equation [21, 22]. + +\begin{equation} +K_{IC} = 0.079 {\left( \frac{P}{a^{\frac{3}{2}}} \right)}log{\left(\frac{4.5 a }{c}\right)} +\end{equation} + +where \(P\) is indenter load \([\textrm{mN}]\), \(2c\) is the crack length \(\left[\mu\textrm{m}\right]\), and \(2a\) is the length of indentation diagonal \(\left[\mu\textrm{m}\right]\) +\end{enumerate} +\section{Electrochemical measurement} +\label{sec:org2ef10c6} +A Corrtest CS310 potentiostat was used for electrochemical experiments in a conventional three electrode cell, with the sample as working electrode with exposed area 2cm2, a saturated calomel electrode (SCE) as reference electrode, graphite plate as counterelectrode, and naturally aerated 3.5\% NaCl solution at room temperature as electrolyte. + + +After attaching wires to the back of samples with copper tape, epoxy resin was used to seal the sample, ensuring only one surface was exposed. This surface was then ground and polished with 220, 600, \& 1000 grit silicon carbide sandpaper, followed by 15um, 6um, 1um, and 0.25um diamond paste. The specimens were rinsed with distilled water, followed by sonication in acetone for 5 minutes, and air-dried for 5 minutes. All samples were freshly prepared before commencement of electrochemical tests. + +For all testing, the OCP was monitored for 1 h to ensure steady state conditions, before the electrical impedence spectroscopy (EIS), LPR, and cyclic voltametry (CV) experiments, in addition to a 24 hour exposure period to measure the change of OCP over time. + +The EIS spectra was measured across a frequency range of 10\textsuperscript{5} Hz to 10\textsuperscript{1} Hz and an excitation voltage of 10mV, with 20 evenly spaced frequencies per decade. Duplicate spectra and additional EIS tests conducted at an excitation voltage of 20 mV were measured to verify the validity of the test data \sidenote{EIS should be independent of the excitation voltage}. +The obtained spectrum was analyzed with the help of Nyquist and Bode plots and equivalent circuit fitting using Corrtest ZView software. +\section{Experimental electrochemical - polarize electrode to -1.5 to remove oxides} +\label{sec:org9b0d1a2} + +Passivation and corrosion behaviours of cobalt and cobalt–chromium–molybdenum alloy +Author links open overlay panelM. Metikoš-Huković +, R. Babić +\url{https://www.sciencedirect.com/science/article/pii/S0010938X07000819} +\section{Description of constant phase element} +\label{sec:org8769844} +\section{Other stuff} +\label{sec:org0639ded} + + +A magnetostrictive vibratory apparatus, operating in general accordance with ASTM Standard G32, was utilized. The system functioned at an ultrasonic frequency of 20 kHz, with a peak-to-peak displacement amplitude of the horn tip maintained at 96 µm. The horn, fabricated from a cavitation-resistant titanium alloy, featured a flat tip of 16 mm diameter. Experiments were conducted using a stationary specimen configuration, with the specimen positioned 0.5 mm below the vibrating horn tip, this distance being precisely set using a dial gauge. + + + +The aqueous oxidation of Stellite 6 alloy was investigated in a 1979 study using X-ray Photoelectron Spectroscopy (XPS) \cite{mcintyreXRayPhotoelectronSpectroscopic1979}. Specimens were exposed to pH 10 water at 285°C. To understand the oxidation behavior, the study measured dissolved oxygen concentration against exposure duration. + + +The high-temperature corrosion resistance of stellite coatings is attributable to the formation of cobalt \& chromium surface \cite{cesanekDeteriorationLocalMechanical2015}. + + +Heathcock et al found that carbides are selectively eroded, with the carbide-matrix interface acting as initiating erosion site \cite{heathcockCavitationErosionCobaltbased1981}. +\begin{enumerate} +\item Paragraph 4: Synergistic Challenges in Applications Prone to Corrosion and Cavitation\hfill{}\textsc{ignore} +\label{sec:orgd00ec53} +\item Paragraph 5: Research and Development for Enhanced Corrosion and Cavitation Performance\hfill{}\textsc{ignore} +\label{sec:org2abbc42} + +\item Paragraph: Cavitation Erosion Resistance +\label{sec:orge8142fa} + + +The primary result of an erosion test is the cumulative mass loss versus time, which is then converted to volumetric loss and mean depth of erosion (MDE) versus time for the purposes of comparison between materials of different densities. The calculation of the mean depth of erosion for this test method should be performed in conformity with ASTM G-32. +\item General Background +\label{sec:org6836cf4} +\%cite:@Franc2004265, @Romo201216, @Kumar2024, @Kim200685, @Gao2024, @20221xix, @Usta2023, @Cheng2023, @Zheng2022 + +Cavitation erosion presents a significant challenge in materials degradation in various industrial sectors, including hydroelectric power, marine propulsion, and nuclear systems, stemming from a complex interaction between fluid dynamics and material response \cite{francCavitationErosion2005, romoCavitationHighvelocitySlurry2012}. Hydrodynamically, the phenomenon initiates with the formation and subsequent violent collapse of vapor bubbles within a liquid, triggered by local pressures dropping to the saturated vapor pressure. These implosions generate intense, localized shockwaves and high-speed microjets that repeatedly impact adjacent solid surfaces \cite{gevariDirectIndirectThermal2020}. From a materials perspective, these impacts induce high stresses (100-1000 MPa) and high strain rates, surpassing material thresholds and leading to damage accumulation via plastic deformation, work hardening, fatigue crack initiation and propagation, and eventual material detachment. Mitigating this requires materials capable of effectively absorbing or resisting this dynamic loading, often under demanding conditions that may also include corrosion. + + +\% Martensitic transformation +Crucially, the cobalt matrix often possesses a low stacking fault energy, facilitating a strain-induced martensitic transformation from a metastable face-centered cubic \(\gamma\) phase to a hexagonal close-packed \(\epsilon\) phase under the intense loading of cavitation. This transformation is a primary mechanism for dissipating impact energy and enhancing work hardening, contributing significantly to Stellite's characteristic cavitation resistance \cite{huangMicrostructureEvolutionMartensite2023, tawancyFccHcpTransformation1986}. + +HIPing is a thermo-mechanical material processing technique which involves the simultaneous application of pressure (up to 200 MPa) and temperature (2000 C), which results in casting densification, porosity closure, and metallurgical bonding. \cite{yuComparisonTriboMechanicalProperties2007} + +While commonly applied via casting or weld overlays, processing routes like Hot Isostatic Pressing (HIP) offer potential advantages such as microstructure refinement \cite{stoicaInfluenceHeattreatmentSliding2005} finer microstructures and enhanced fatigue resistance \cite{ahmedInfluenceReHIPingStructure2013, yuComparisonTriboMechanicalProperties2007}. + +HIPing of surface coatings results in microstructure refinement, which can yield improved fatigue and fracture resistance. + +HIPing leads to carbide refinement, which can yield improved impact toughness \cite{yuInfluenceManufacturingProcess2008}, and reduce carbide brittleness \cite{yuComparisonTriboMechanicalProperties2007}. + +Furthermore, HIP facilitates the consolidation of novel 'blended' alloys created from mixed elemental or pre-alloyed powders, providing a pathway to potentially tailor compositions or microstructures for optimized performance. However, despite the prevalence of Stellite alloys and the known influence of processing on microstructure and properties, the specific cavitation erosion behavior of HIP-consolidated Stellites, particularly these blended formulations, remains underexplored in academic literature. Given that erosion mechanisms in Stellites often involve interactions at the carbide-matrix interface \cite{szalaEffectNitrogenIon2021}, understanding how HIP processing and compositional blending affect these interfaces and the matrix's transformative capacity under cavitation, especially when potentially coupled with corrosion, constitutes a critical knowledge gap addressed by this research. + + +\% Need to describe Stellite 1 +\section{Stellite 1} + +Stellite 1 is a high-carbon and high-tungsten alloy, making it suitable for demanding applications that require hardness \& toughness to combat sliding \& abrasive wear \cite{crookCobaltbaseAlloysResist1994} + + + + +\section{Stellites} +\section{Objectives and Scope of the Research Work} +\section{Thesis Outline} +\section{Literature Survey} +\section{Cavitation Tests} +\end{enumerate} +\section{Charpy impact energy} +\label{sec:orgad58270} + + +\begin{center} +\begin{tabular}{llll} + & Macrohardness & Microhardness & Charpy Impact Energy\\ + & HV, 294N & HV 2.94N & J\\ +Cast Stellite 20 & 653.4 pm 18.7 & 759 pm 98 & 1.36 pm 0\\ +HIPed Stellite 20 & 675 pm 17.2 & 704 pm 15 & \\ +\end{tabular} +\end{center} +\chapter{Results and Analysis} +\label{sec:orge814e9c} + +\section{Microstructure and Phase Analysis} +\label{sec:orgd9dd52d} + + +Cast Stellite 1 has a hypereutectic structure consisting of M7C3 primary carbides, M6C eutectic carbides, and matrix. HIPed Stellite 1 show the same phases but with much finer structure, with fine carbides uniformly distributed in the matrix. + +The different variants of the S1 alloy show a similar content of carbides of type M7C3 with 22–24 vol.-\%. However, the M6C content of the HIP variant at 15.8 vol.-\% is almost twice as high as that of the cast or welded variant. Accordingly, the total carbide content of the S1 alloys investigated varies between 29.3 and 37.5 vol.-\%. +\section{Microstructure and Phase Analysis} +\label{sec:org6206842} + +The microstructures of the gas atomised powder particles, cast and HIPed alloys are shown in Fig. 2. + +The possible phases in the powders were identified via XRD as α-Co (F.C.C.), Cr, Cr23C6, Co6W6C, Co3W, and Co7W6. Fig. 2b shows the hypoeutectic microstructure of the cast alloy, which consists of Co-rich dendrites (dark region), Cr-rich eutectic phase (grey phase), and W-rich carbide (bright phase). + +Table II presents the image analysis results of the area fractions of various phases in the cast and HIPed structures. + +The XRD analysis revealed that α-Co was the primary phase in the Co-rich solid solution, whilst tungsten was also present in the solid solution, which strengthened it by forming the inter-metallic compounds Co3W and Co7W6. + +The Cr-rich eutectic phase was unlikely to be pure Cr23C6 carbide as identified via the XRD analysis, because the relatively lower carbon content (0.9wt.\%) of the alloy could not lead to such high area fraction (27.7\%) of carbides. + +This phase could be a mixture of Cr23C6 carbides and CoCrW solid solution, as the EDS analysis showed that it consisted of small proportions of Co and W, besides Cr and C. The bright phase was identified as W-rich carbide, Co6W6C. The microstructure of the HIPed alloy (Fig. 2c) consisted of three types of phases, which were uniformly distributed in the matrix (dark region, with an area fraction of 65.8\%). The EDS analysis revealed that the light grey phase contained around 35\% Co, 28\% Cr, and 37\% W (in wt.\%), indicating that this phase was also CoCrW solid solution, which differed from the matrix phase in terms of its tungsten content. The dark grey phase was Cr-rich carbide with an approximate composition of (Co0.22Cr0.70W0.08)23C6. The bright phase was identified as W-rich carbide. The XRD analysis indicated that the possible phases in the HIPed alloy were α-Co, Cr7C3, Cr23C6, Co6W6C, Co3W, and Co7W6. Most of these phases were inherited from the powders, except for the Cr7C3, indicating that it was formed during the HIPing process. + +In comparison to the cast alloy, the microstructure of the HIPed alloy was not only finer, but also had discrete carbides, instead of the interconnected three-dimensional eutectic net observed in the cast structure. + +The difference in the microstructure can have a significant influence on the tribo-mechanical properties. As discussed later, the impact toughness and fatigue resistance, which involved failure mechanisms that were dependent upon crack propagation, benefited from the absence of a three-dimensional eutectic net in the HIPed alloy. However, there was a trade-off between these improvements, and the wear resistance of the HIPed alloy, as the difference in carbide morphology caused changes in the wear mechanisms. + + + + + +Figures 2 and 3 provide the SEM and XRD comparison of the cast and HIPed alloys. Figure 2 a shows the SEM of the dendritic microstructure on the spherical surface of the gas-atomized powder. Figure 2 b and 2 c show the hypoeutectic microstructure of the cast alloy, which consists of Cr-rich carbides dark phase , W-rich carbides bright phase , and the Co-rich dendritic matrix gray region . Figure 2 d shows the SEM observation of the HIPed alloy, with finer carbides dark phase uniformly distributed in a Co-rich matrix gray region . The image analysis results of the area fractions of various phases are presented in Table 2. Previously reported 20 image analysis results for Stellite 20 alloys are also presented in this table to aid the discussion. + +The cast CoCr28W alloy had a hypoeutectic microstructure Figs. 2 b and 2 c , which consists of Corich dendrites gray region , set in lamellar eutectic Cr-rich dark phase and W-rich bright phase carbides. The Cr-rich eutectic carbide had a composition of Cr0.71Co0.25W0.03Fe0.005 7C3, as approximated by the EDS analysis. The XRD analysis Fig. 3 c revealed that the carbides were Cr7C3 and Co6W6C, while -Co fcc was the primary phase in the solid solution, together with the intermetallic compounds, Co3W and Co7W6. + +This dendritic microstructure is typical of the cast CoCr28W alloy in which the carbide and grain size can be controlled by the rate of cooling. Within the family of cast cobalt-based alloys, the relatively large carbide size seen in the cast microstructure indicated slow freezing during the casting process. The microstructure of cast Stellite 6 alloys was a topic of research for a number of investigations and further details of the influence of the cooling rate on the grain size of cast cobalt-based alloys can be appreciated elsewhere 13 . The scope of the discussion here is therefore its microstructural comparison with the HIPed counterpart in terms of understanding the structure-property relationships during tribomechanical performance. The HIPed alloy had a much finer microstructure Fig. 2 d with Cr-rich carbides dark phase uniformly distributed in the matrix. + +The typical carbide size was 1 – 3 m, which was much finer than the cast counterpart. There was no bright W-rich phase observed in the HIPed microstructure, which could be attributed to the fast solidification in the powder manufacturing process, restricting the segregation of W-rich zones. Subsequently during HIPing of the powder, tungsten remained evenly distributed throughout the alloy because its large atomic radius hinders diffusion. This evolution of the HIPed microstructure was therefore fundamentally different from the dendritic microstructure of the cast alloy, which was caused by the rejection of elemental species in the melt during the crystal growth of Co-rich dendrites. Hence above the liquidus line of this complex Co alloy, elemental species were free to arrange themselves depending on the thermal kinetics of the mold without any dependency on diffusion, and hence a truly three-dimensional network of carbides was formed. Contrary to this, in the case of HIPed microstructure, the primary dendrites formed on the alloy powder Fig. 2 a , and the carbides in the powder particles Fig. 3 a promoted carbide growth due to the diffusion of carbon and other elemental species within and across the individual powder particle boundaries. + +As this diffusion process is time, temperature, and pressure dependent during HIPing, and the HIPing temperature 1200° C in this investigation was lower than the melting point of the powder, carbide growth was sluggish when compared with casting. Hence the size of individual carbide particles was much smaller than the cast counterpart. + +Although not reported in Sec. 3, authors also found that re-HIPing the HIPed alloy under similar conditions as were reported earlier in Sec. 2.1 did not substantially increase the average carbide size, indicating that carbide growth was more dependent on temperature than time during the HIPing process. The XRD analysis Fig. 3 b revealed that the possible phases in the HIPed alloy were Cr7C3, -Co, Co3W, and Co7W6, which were similar to those in the cast alloy, except the absence of Co6W6C. The intermetallic compound, Co7W6, was not identified in the atomized powder, indicating that it was formed during the HIPing process. The pure Cr phase in the powder, which formed due to the rapid solidification, was not identified in the HIPed alloy, indicating that it either combined with the cobalt matrix, or formed carbides. The image analysis Table 2 showed that the cast alloy had an approximate total carbide fraction of 15.5\%, which was slightly less than that of the HIPed alloy 17.9\%. + +These values indicated on average a 63\% reduction in the carbide content when compared with the Stellite 20 alloy, which can be attributed to the lower carbon and tungsten content in the Stellite 6 alloys. These differences in the microstructure, carbide content, and morphology had a significant influence on the tribomechanical performance, as discussed in the following sections. + + +4.1 Microstructure. The microstructure of cobalt-based Stellite alloys has been the topic of research for almost a century and a number of investigations have discussed their microstructure on the basis of alloy composition and processing route 4,5,10–17 . However, comparative analysis of the microstructure of these alloys is scarce in the published literature. The aim of the discussion here is therefore to highlight the differences in the microstructure of the two alloys, with a view to underpin the understanding of structure–property and tribo-mechanical behavior. The cast alloy had a hypereutectic microstructure, which was typical of cobalt-based alloys of this composition. The primary idiomorphic carbide was Cr-rich M7C3, with a composition of Cr0.75Co0.20W0.05 7C3, as approximated by the EDS analysis. These are rod like carbides, a section of which can be seen as the dark blocky carbide in Fig. 2 b . It was surrounded by the dendritic CoCrW solid solution grey region . The final phases to solidify were the lamellar eutectic phases containing both the Crrich dark and W-rich light carbides. The three-phase area shown in Fig. 2 b indicates the simultaneous occurrence of both primary carbides and CoCrW dendrites in the microstructure. The XRD analysis Fig. 3 b revealed that the carbides were Cr7C3, Cr23C6, and Co6W6C, while the primary phase in the solid solution was -cobalt fcc , together with the intermetallic compounds, Co3W and Co7W6. Hence, in the cast alloy, there were three kinds of carbides, i.e., the relatively large blocky Cr-rich carbides, the interconnected three-dimensional W-rich eutectic carbides, and the relatively smaller Cr-rich eutectic carbides, which coexisted in the microstructure. The HIPed alloy had a finer microstructure Fig. 2 c with Cr-rich dark and W-rich light carbides uniformly distributed in the matrix. These carbides were typically 2 m in size and much finer than the large blocky carbides observed in the cast alloy. Despite different microstructure, the possible phases identified in the HIPed alloy were similar to those in the cast alloy Fig. 3 . These phases seemed to be inherited from the atomized powders, except for the replacement of Co3W3C by Co6W6C. The pure chromium phase identified in the powder, which formed due to the rapid solidification from the molten state during the atomization process, was not identified in the HIPed alloy. This indicated that it either was combined with cobalt, or formed carbides, and no longer existed as a pure phase after the HIPing process. The total volume fraction of carbides Table 2 was nearly 50\% in the HIPed alloy, which were uniformly distributed in the metal matrix Fig. 2 c . The differences in the carbide morphology of both alloys can have a significant influence on their tribomechanical properties. In terms of the structure–property relationships, as discussed in later sections, the failure mechanisms, which were very much dependent upon crack propagation, e.g., impact and fatigue strength, therefore benefitted significantly from the absence of a three-dimensional eutectic net in the HIPed alloy. However, there was a tradeoff between the improved impact strength and relatively lower wear resistance due to smaller carbides in the HIPed alloy, because of the changes in the wear mechanisms during the abrasive and sliding wear of the two alloys. The image analysis Table 2 indicated that despite similar volume fractions of Cr-rich carbides in both alloys, the approximate W-rich carbides content in the HIPed alloy 24.7\% was more than that in the cast alloy 18.1\% . In view of the higher carbide content, one might expect superior abrasive and sliding wear performance of the HIPed alloy. However, as discussed later, the changes in the wear mechanisms due to the relatively smaller size of carbides observed in the HIPed microstructure, did not provide significant abrasive wear improvement over the cast counterpart. +\section{Electrochemical corrosion tests} +\label{sec:org093aec4} +\begin{enumerate} +\item Open circuit potential measurement +\label{sec:org95ec7c8} + +These two below do a great job of + +Open circuit potential measurements observe the unaltered corroding potential in the absense of any applied external voltage/current, with passivating alloys expected to reach a steady state potential \cite{rosalbinoCorrosionBehaviourAssessment2013, ogunlakinMicrostructuralElectrochemicalCorrosion2025}, in order to establish an equilibrium condition from which to perform further electrochemical tests. As seen in Fig <>, the HIPed Stellite 1 initially shows an OCP of <> mV (SCE) which increases to more noble potentials, reaching <> mV (SCE) after 24 hours, while the cast Stellite 1 specimen shows an initial OCP of <> mV (SCE) which increases to <> mV (SCE) after the same exposure duration. + +Although both HIPed and cast specimens are observed to have OCPs drift towards less negative potentials, which is indicative of the formation of a passivative oxide film, the HIPed alloy consistently shows higher OCP values, suggesting a greater thermodynamic inclination for oxide film formation and better corrosion protection in 3.5\% NaCl solution. +\item Polarization Tests +\label{sec:orgb8aa2fd} +\end{enumerate} +\section{Strain hardening} +\label{sec:orgd1d2f20} + +Cavitation bubble collapses cause significant plastic deformation and strain-induced work hardening in the near-surface of ductile materials, characterizized by the thickness of the hardened layers and the shape of the strain profile below the surface \cite{berchicheCavitationErosionModel2002}. + +In cobalt-based alloys, work hardening is primarily attributable to a strain-induced martensitic phase transformaion from the metastable \(\gamma-Co\) phase to the harder \(\epsilon-Co\) phase. Woodford's investigations on the \$\(\gamma\)\$\textrrightarrow\(\epsilon\) transformation on the surface of cobalt-base alloys during cavitation erosion, the transformed layer was found to extend to a depth of 25 to 50 \um through XRD analysis \cite{woodfordCavitationerosionlnducedPhaseTransformations1972}, with the percentage of transformation remaining constant with cavitation erosion. + + +This analysis was first proposed by Karimi \& Leo in 1987 \cite{karimiPhenomenologicalModelCavitation1987} and adapted by Berniche et al in 2002 \cite{berchicheCavitationErosionModela}, and Franc \cite{francIncubationTimeCavitation2009} in 2009. + +The strain profile within the material can usually be modeled by the following power law: + +\begin{equation} +\epsilon\left(x\right) = \epsilon_s {\left( 1 - \frac{x}{L} \right)}^{\theta} +\end{equation} + +where \(\epsilon\left(x\right)\) is the strain at depth \(x\) from the eroded surface, \(\epsilon_s\) is the failure rupture strain on the eroded surface, \(L\) is the thickness of the hardened layer, \(\theta\) is the shape factor of the power law. The parameters \(L\) and \(\theta\) are determined from the microhardness measurements on cross sections of the cavitation affected region. + + + +The strain hardening effect after erosion tests was calculated from the following formula: + +\begin{equation} +\Delta{}HV = \dfrac{{HV}_{x} - {HV}_{0}}{{HV}_{0}} \cdot 100 \% +\end{equation} + +where \({HV}_{x}\) is the hardness at a distance below the cavitation crater, while HV\textsubscript{0} is the initial hardness. +\begin{enumerate} +\item Data for strain hardening\hfill{}\textsc{ignore} +\label{sec:orgfa4ad82} + +\begin{table}[htbp] +\caption{Microhardness HV\textsubscript{0.01} of Al0.1CoCrFeNi HEA \cite{nairExceptionallyHighCavitation2018a}} +\centering +\begin{tabular}{rr} +x & y\\ +15.025380710659899 & 339.3103448275862\\ +29.949238578680202 & 277.2413793103448\\ +44.87309644670051 & 212.0689655172414\\ +59.974619289340104 & 230.34482758620692\\ +74.89847715736042 & 203.10344827586206\\ +89.82233502538071 & 203.44827586206895\\ +104.74619289340102 & 195.86206896551724\\ +120.0253807106599 & 195.86206896551724\\ +135.12690355329948 & 187.58620689655174\\ +150.2284263959391 & 155.86206896551724\\ +164.9746192893401 & 153.10344827586206\\ +\end{tabular} +\end{table} + +\begin{table}[htbp] +\caption{Microhardness HV\textsubscript{0.01} of 316LSS \cite{nairExceptionallyHighCavitation2018a}} +\centering +\begin{tabular}{rr} +x & y\\ +14.847715736040609 & 288.62068965517244\\ +29.77157360406091 & 251.72413793103448\\ +45.0507614213198 & 240\\ +59.974619289340104 & 219.31034482758622\\ +74.89847715736042 & 227.24137931034483\\ +89.82233502538071 & 228.9655172413793\\ +104.9238578680203 & 221.72413793103448\\ +120.0253807106599 & 218.27586206896552\\ +135.48223350253807 & 224.82758620689657\\ +149.87309644670052 & 225.86206896551727\\ +165.1522842639594 & 224.48275862068965\\ +\end{tabular} +\end{table} +\end{enumerate} +\chapter{Discussion} +\label{sec:orgb148c4d} +\section{Experimental Test Procedure} +\subsection{Hardness Tests} +\subsection{Cavitation} + +\section{Relationships between cavitation erosion resistance and mechanical properties} +\section{Influence of vibratory amplitude} + +\% Insert the whole spiel by that French dude about displacement and pressure (and then ruin it) +The pressure of the solution depends on the amplitude of the vibratory tip attached to the ultrasonic device. Under simple assumptions, kinetic energy of cavitation is proportional to the square of the amplitude and maximum hammer pressure is proportional to A. + +\begin{align} +x &= A sin(2 \pi f t) \\ +v &= \frac{dx}{dt} = 2 \pi f A sin(2 \pi f t) \\ +v_{max} &= 2 \pi f A \\ +v_{mean} &= \frac{1}{\pi} \int^\pi_0 A sin(2 \pi f t) = 4 f A \\ +\end{align} + +However, several researchers have found that erosion rates are not proportional to the second power of amplitude, but instead a smaller number. +Thiruvengadum \cite{thiruvengadamTheoryErosion1967} and Hobbs find that erosion rates are proportional to the 1.8 and 1.5 power of peak-to-peak amplitude. +Tomlinson et al find that erosion rate is linearly proportional to peak-to-peak amplitude in copper [3]. +Maximum erosion rate is approximately proportional to the 1.5 power of p-p amplitude [4]. +The propagation of ultrasonic waves may result in thermal energy absorption or into chemical energy, resulting in reduced power. For the purposes of converting data from studies that do not use an amplitude of 50um, a exponent factor of 1.5 has been applied. +\section{Correlative empirical methods} +\label{sec:org641b696} + +Empirical methods are common for addressing complex cavitation erosion, involving lab tests to correlate cavitation erosion resistance with mechanical properties. +\begin{enumerate} +\item Karimi and Leo +\label{sec:orge58f70e} + +The Karimi and Leo phenomenological model describes cavitation erosion rate as a function of + +Karimi and Leo +\item Noskievic +\label{sec:org89db042} + +Noskievic formulated a mathematical relaxation model for the dynamics of the cavitation erosion using a differential equation applied to forced oscillations with damping: + +\begin{equation} +\frac{\mathrm{d}^2 v }{\mathrm{d}t^2} + 2 \alpha \frac{\mathrm{d} v }{\mathrm{d}t} + \beta^2 v = I +\end{equation} + +where \(I\) is erosion intensity, which can vary linearly with time, \(v = \frac{\mathrm{d} v }{\mathrm{d}t}\) is erosion rate, \(\alpha\) is strain hardening or internal friction of material during plastic deformation, and \(\beta\) is coefficient inversely proportional to material strength. The general solution of equation can be written as: + +\begin{equation} +v = a f_0 \left( \delta, \tau \right) + b f_1 \left( \delta, \tau \right) +\end{equation} + +\begin{equation} +f_0\left(\ \delta,\tau \right) = \left\{ \begin{array}{@{}lr@{}} +1 - \mathrm{exp}{ \left( - \delta \tau \right) } \left[ \dfrac{\delta}{\omega} \mathrm{sin} \left(\omega \tau\right) + \mathrm{cos}{\left( \omega \tau \right)} \right] +& \text{if } -1 < \delta < 1; \delta \neq 0 \\ +1 - \dfrac{1}{ {{\delta_0}^2} - 1} \left[ \delta_0^2 \mathrm{exp}{\left( -\dfrac{\tau}{\delta_0}}\right) - \mathrm{exp}{\left(- \delta_0 \tau\right)} \right] +& \text{if } \delta > 1 \\ +1 - \mathrm{cos}{\left( \tau \right)} +& \text{if } \delta = 0 \\ +1 - \left(1 + \tau \right) \mathrm{exp} \left( - \tau \right) +& \text{if } \delta = 1 +\end{array} \right\} \\ +\end{equation} +\begin{equation} +f_1\left(\ \delta,\tau \right) = \left\{ \begin{array}{@{}lr@{}} +1 - \dfrac{2\delta}{\tau} \left[ 1 - {\mathrm{exp}\left(-\delta \tau\right)} {\left[ {\mathrm{cos} \omega \tau} + {\epsilon \mathrm{sin} \omega \tau} \right]} \right] +& \text{if } -1 < \delta < 1; \delta \neq 0 \\ +1 - \dfrac{1}{\tau} \left( 2 \delta - \dfrac{1}{\delta_0 \left( \delta_0^2 - 1 \right)} \left[\mathrm{exp}{\left( -\delta_0 \tau \right) - \delta^4 \mathrm{exp}{\left( \dfrac{-\tau}{\delta_0} \right)} \right] \right) +& \text{if } \delta > 1 \\ +1 - \dfrac{ \mathrm{sin}{\left( \tau \right)} }{\tau} +& \text{if } \delta = 0 \\ +1 - \dfrac{2 \left[ 1 - \mathrm{exp}\left(-\tau\right) \right]}{\tau} + \mathrm{exp} \left( - \tau \right) +& \text{if } \delta = 1 +\end{array} \right\} +\end{equation} +\begin{equation} +\delta = \dfrac{\alpha}{\beta},\quad +\tau = \beta t,\quad +\epsilon = \dfrac{\delta^2 - 0.5}{\delta \sqrt{ 1 - \delta^2 } },\quad +\omega = \sqrt{1 - \delta^2},\quad +\delta_0 = \delta + \sqrt{ \delta^2 - 1 } +\end{equation} +\item Hoff and Langbein equation +\label{sec:org14c55ad} + +Hoff and Langbein proposed a simple exponential function for the rate of erosion, representing the normalized erosion rate requiring only the +A simple exponential function for the rate of erosion was proposed by Hoff and Langbein, + +$$ \frac{ \dot{e} }{ \dot{e_{max}} } = 1 - e^{\frac{-t_i}{t}} $$ + +\(\dot{e}\) - erosion rate at any time t +\(\dot{e_{max}}\) - Maximum of peak erosion rate +\(t_i\) - incubation period (intercept on time axis extended from linear potion of erosion-time curve) +\(t\) - exposure time +\item L Sitnik model +\label{sec:org8cad6ec} + +$$ V = V_o {\left[ ln\left( \frac{t}{t_o} + 1 \right) \right]} ^ {\beta} $$ + + +$$ \dot{V} = \frac{\beta V_o}{t + t_o} {\left[ ln \left( \frac{t}{t_o} + 1 \right) \right]}^{\beta - 1}$$ + +V\textsubscript{o} > 0 +t\textsubscript{o} > 0 +\(\beta\) >= 1 +\end{enumerate} +\chapter{Conclusions} +\label{sec:orge3fdfff} +\part{Weird hanger-ons} +\label{sec:org1d08aa9} +\chapter{Erosion particles} +\label{sec:org95ea6be} + +\url{https://www.sciencedirect.com/science/article/pii/S0264127525003065} +Experimental investigation of cavitation erosion-induced surface damage and particle shedding from PTFE + +Is for PTFE, but the depth of analysis is excellent +\chapter{Reasons for why CE is less in seawater} +\label{sec:org53d9aa8} +\url{https://www.sciencedirect.com/science/article/pii/S0043164825000614} +\chapter{Residual Stress and why it's important} +\label{sec:org4c171d7} + +There is a direct relationship between the cavitation intensity and +changes in the residual surface stresses: the higher the level of the cavita- +tion intensity the faster is the build-up of compressive residual stress. +However, the maximum value of the cavitation-induced stresses does not +depend on the intensity of cavitation. After a sufficiently long attack time +the same maximum value is reached, even at points of lowest cavitation +intensity. +The reduction in compressive residual stress which can be observed +after a long cavitation time is due to the plasticity being exhausted and the +related formation of microcracks. +During the initial phase of the attack, up to the time the limiting stress +value is reached, the local variation in cavitation intensity may be very +clearly seen in the stress distribution in the surface. Based on the residual +stress distribution, it can be ascertained at which point there is a minimum +or maximum cavitation intensity and where the removal of the material +initially takes place. X-ray residual stress analysis can therefore be valuable +for the early detection of cavitation processecs +\chapter{Why HIP is better than cast} +\label{sec:org0b5eb82} + +The microstructure in the Stellite alloys produced by using casting method consisted of the dendrites formed by the Co solid solution and the eutectic carbide phases between these dendrites. The carbides were in the form of continuous films surrounding the grains and had a large size [5], [15], [25], [26], [33]. In the alloys produced by casting, this shape, size, and distribution style of the carbides decreased ductility and fatigue strength of the material [34]. In the present study, it was observed in the material produced by using PIM that the non-interconnected carbides with the block morphology had a homogenous distribution on the grain boundaries throughout the microstructure instead of large size eutectic carbides surrounding the dendrites. Various studies have reported that the carbides exhibited such a distribution in the Stellite alloys produced by using HIP and they had a spherical-like form [5], [15], [25]. The morphology of the carbide precipitates in superalloys has significant effects on the properties of alloys. The fact that carbide precipitates at the grain boundaries in the form of a continuous film sets a ground for the formation of cracks and decreases significantly the impact and rupture properties of the alloy. Since the formation of precipitates that are large and independent from each other (discrete) at the grain boundaries, instead of a continuous film, prevents dramatically the grain boundary sliding, it is useful [23], [35]. Additional heat treatments are needed in Co alloys produced by casting in order to obtain a more homogenous structure by dissolving the large carbide network and thus to improve the mechanical properties [34]. Taking into account these explanations and in contrast to the Stellite alloys produced by casting, it is also expected for the PIM method, which provides the acquiring of materials containing carbides exhibiting finer and more homogenous distribution without needing additional heat treatments, to provide more superior mechanical properties. +\chapter{Equiaxed grains - why HIP is better than cast} +\label{sec:org1801739} + +Numerous previous studies have reported that the materials produced by using PIM consist of equiaxed grains as in this study [18], [19], [20], [21]. The controlling of the grain size is very significant to develop and sustain the physical and mechanical properties among the materials. + +In this study, the superior properties such as homogenous microstructure, fine and equiaxed grains easily obtained by using PIM technique without needing any precaution were rather difficult to be obtained by using casting method. +\chapter{Describing SEM images (light gray, dark, light)} +\label{sec:org1d136b7} + +It can be seen from the SEM images in Fig. 8 that the microstructure included light colored and dark colored phases although no etching process was performed. In the previous studies conducted concerning Stellite alloys, it is reported that the Co matrix in the microstructure was light gray and the carbides rich in Cr were dark gray [3], [5], [15], [26], [29]. It is indicated that W element also forms carbides in Co based superalloys and the carbides formed by W were of a brilliant white color in the microstructure [26]. Based on these explanations, it can be asserted that the dark precipitates homogenously distributed in the microstructure in the SEM images of the samples taken without etching them in this study were the carbides formed by Cr. +\chapter{Stellite 1} +\label{sec:orge4c106f} + +\chapter{Parametric studies on Stellite} +\label{sec:org28cdb9c} + + +Accelerated discovery of composition-carbide-hardness linkage of Stellite alloys assisted by image recognition +\url{https://doi.org/10.1016/j.scriptamat.2023.115539} + +Abstract +Stellite alloys are widely utilized in the aerospace industry due to their excellent hardness and high wear resistance. Optimal properties are predominantly achieved through engineering desired microstructures in terms of type, size, shape, and spatial distribution of carbides within the Co-Cr matrix through alloying. However, a quantitative linkage among composition, carbide, and hardness (CCH) is still lacking. Herein, we attempt to tailor the essential reinforcement elements, Mo and C, to obtain different Stellite alloys using powder metallurgy (PM). With the help of image recognition technology, microstructures of alloys (including the type and content of carbides, as well as the content of defects.) were quantitatively analyzed. Besides, mathematical algorithms based on Analysis of Variance (ANOVA) and Desirability Functional Analysis (DFA) were developed to establish the models for the quantification of CCH. Specifically, the regression equations provide the quantitative relationship between elements (Mo and C), two primary carbides (M7C3 (M=Metal) and M23C6), and the hardness. We believe this quantitative work assisted by image recognition would be beneficial for the development of Stellite alloys and could shed light on the CCH relationship of other cemented carbides alloys. + +Link between Composition/Carbide/Hardness + +In general, the chemical composition of Stellite alloys determines the type and content of carbide thus the related mechanical properties. Therefore, the linkage between composition, carbide, and hardness characteristics (CCH) has always been a focus of substantial Stellite alloy studies [3,4,[7], [11], [12], [13], [14]]. + +Besides, we used the Thermo-Calc software [26] and TCHEA5 thermodynamic database [27] to calculate the phase fraction of each sample at different temperatures as shown in the Fig. S5. The thermodynamic calculation well verified that there is no M23C6 carbide in the S3 sample. What's more, as shown in the following Table 5, we listed the phase fraction and temperature which are closest to the experimental results according to the CALPHAD results. + + + + + + +\label{Bibliography} +\printbibliography[title={References}, heading=bibintoc, resetnumbers=true] +\end{document} diff --git a/Untitled.ipynb b/Untitled.ipynb new file mode 100644 index 0000000..970590d --- /dev/null +++ b/Untitled.ipynb @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4b47f5f379d722a0341bfcfa7ca2e1d9045f5bab225443a5c42505bef3fe280a +size 144241 diff --git a/cavitation_erosion_data.xlsx b/cavitation_erosion_data.xlsx new file mode 100644 index 0000000000000000000000000000000000000000..96187a5c5df7b083f65203d0a4e6978559f06dae GIT binary patch literal 56889 zcmeFXgL9<8|1LVQ&5fOn?QF6e+nLz5ZF^(ewrxzbv5n2fwr;-ncTU}N>Yo4Lciwty zrlzOgnwoz4L4Udxq#+fiwY3;-;+mav_zvx%*Z17h*C!Izv}FRaMcIL0d1Y&Ng8dhe=pFMQUpdbPuP` z>j!Lf=dRFSn<1+`yE6%`&Q1i6QE7%QryNDIG&_cQjtj!WZQ_fP&)a 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Uf-R9Jonc(js|@u=%7@s!f9A%JtN;K2 literal 0 HcmV?d00001 diff --git a/cavitation_models.org b/cavitation_models.org new file mode 100644 index 0000000..845ffa3 --- /dev/null +++ b/cavitation_models.org @@ -0,0 +1,16 @@ +#+TITLE: Cavitation Models +#+AUTHOR: Vishakh Pradeep Kumar + + + + + + +karimiPhenomenologicalModelCavitation1987 + + +$$ \epsilon (x) = \epsilon_s {\left( 1 - \frac{x}{L} \right)}^{\theta} $$ + +Parameters: +maximum width of work-hardening $L$ +shape coefficient $\theta$ diff --git a/literature_review.org b/literature_review.org new file mode 100644 index 0000000..5afe41f --- /dev/null +++ b/literature_review.org @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3ff0920efc9e0118d26f1a324dd0d5769fdbbc6551a4610001fd11d311977770 +size 295950 diff --git a/references.bib b/references.bib new file mode 100644 index 0000000..2dba48b --- /dev/null +++ b/references.bib @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ad5e0df1dc3b10ee165102b3aabad2dcd5c8d72b6ca6c5705705dfe7ae2fd1c9 +size 3123318 diff --git a/rig.org b/rig.org new file mode 100644 index 0000000..d8ae091 --- /dev/null +++ b/rig.org @@ -0,0 +1,16 @@ +#+TITLE: Rig + + + +- [[https://gitlab.com/openflexure/openflexure-block-stage/][A 3D Printable high-precision 3 axis translation stage]] + Use for scanning samples? + +https://arxiv.org/abs/1911.09986 + +Has 2 x 2 x 2 mm3 travel range, with sub 100 nm resolution. + +- [[https://www.printables.com/model/874575-14-od-tube-organizer-with-zip-ties][1/4" OD Tube Organizer with Zip-ties]] + Use for organizing the water/vacuum/air pressure tubes? + + +# diff --git a/stellite.org b/stellite.org new file mode 100644 index 0000000..68f5a85 --- /dev/null +++ b/stellite.org @@ -0,0 +1,57 @@ + + +Overall Structure: A Progressive Unveiling of Stellite Alloys + +The introduction follows a logical progression: +- [ ] What they are and where they came from. + + [ ] Identification as Cobalt-base (Stellite) superalloys. + + [ ] Core beneficial properties + high strength, corrosion resistance, high-temperature hardness + + [ ] Pioneering figure (Elwood Haynes) and seminal alloy + Stellite 6 with nominal composition + + [ ] Brief mention of other significant early alloys and their initial scope of applications. +- [ ] Fundamental Strengthening Mechanisms + + [ ] Primary mechanism: Hard carbide precipitation (e.g., M$_{7}$C$_{3}$, M$_{23}$C$_{6}$), with dependence on carbon content and processing. + + [ ] Secondary mechanism: Solid solution strengthening by specific elements (W, Mo, Cr), also linked to carbon content. + + [ ] Additional mechanism: Stress-induced phase transformation (fcc to hcp) contributing to wear resistance via work hardening. +- [ ] How they are made and modified. +- [ ] Current research directions and future outlook. + + + + + +Cobalt-base (Stellite) superalloys are valued for their high strength, corrosion resistance, and hardness, especially at high temperatures. + +Originating in the early 1900s with Elwood Haynes's Stellite 6 (nominally Co–28Cr–4W–1.1C wt.%), these materials, alongside other early alloys like Vitallium and X-40, quickly found use in demanding applications, from industrial tools to aerospace components. + +Stellite alloys derive their properties from hard carbides (e.g., M$_{7}$C$_{3}$, M$_{23}$C$_{6}$), whose formation depends on carbon content and processing, and from solid solution strengthening by elements like W, Mo, and Cr, whose effect is also carbon-dependent. A stress-induced face-centered cubic (fcc) to hexagonal close-packed (hcp) phase transformation further enhances wear resistance through work hardening. + +Applications for Stellite alloys have expanded from traditional uses like machine tools and nuclear components to diverse sectors including oil and gas, chemical processing, and medical implants. This wider usage increases the demand for understanding their corrosion and tribo-corrosion performance in aggressive environments. + +Manufacturing processes critically influence Stellite's microstructure (which can be hypoeutectic or hypereutectic) and, consequently, its performance. Beyond traditional casting, modern powder metallurgy techniques like Hot Isostatic Pressing (HIPing) are favored for producing dense, homogenous, near-net shape parts, minimizing internal defects and subsequent machining. Surface engineering methods, including plasma transferred arc (PTA) welding and laser surface melting, further tailor surfaces for specific wear resistance needs, though considerations like substrate dilution effects on corrosion properties are important. + +Current research focuses on enhancing Stellite alloys through strategic alloying additions (e.g., Si, W, Mo) to tailor microstructure, mechanical properties, and corrosion behavior, partly by methods such as stabilizing the fcc phase. The integrity, protective qualities, and repassivation capability of their passive films are vital for resisting localized corrosion. Understanding the complex interplay between alloy composition, processing, microstructure, and performance in corrosive and wear-intensive conditions remains crucial for optimizing these alloys for existing and emerging industrial applications. + + + + + + + + +Cobalt-base (Stellite) alloys have seen extensive use in wear environments mainly due to their high strength, corrosion resistance and hardness Co-base superalloys rely primarily on carbides formed in the Co matrix and at grain boundaries for their strength and the distribution, size and shape of carbides depends on processing condition. Solid solution strengthening of Co-base alloy is normally provided by tantalum, tungsten, molybdenum, chromium and columbium [1]. Since these elements are all carbide formers their effectiveness in terms of solid solution strengthening is dependent on the C content of alloy. Stellite 6 with nominal composition Co–28Cr–4W–1.1C (wt.%) was the first Stellite alloy developed in 1900 by Elwood Haynes. In recent years, there have been investigations into the effect of additions of alloying elements [2] on the microstructure and mechanical properties of Stellite 6. Improved hardness through formation of intermetallic compounds and mixed carbides could be achieved in both cases. It was shown that W and Mo addition influences the corrosion behaviour by stabilising the fcc phase [1]. Recent work by Kuzucu et al. [3] has demonstrated how the addition of 6 wt.% Si can alter the microstructure and hardness of Stellite 6 alloy thus enabling the properties to be tailored towards a specific application. + + +Because Stellite alloys are often used to combat wear there have been numerous studies in which surface engineering strategies to functionalise the surface for a specific application have been assessed. These have included plasma transferred arc (PTA) welding [4], laser surface melting [5] and plasma diffusion treatments [6]. Currently use of Stellite alloys has extended into various industrial sectors (e.g. pulp and paper processing, oil and gas processing, pharmaceuticals, chemical processing) and the need for improving information regarding corrosion (and often tribo-corrosion) of Stellite alloys has increased. It has been recognised that processing changes, which affect the microstructure of Stellite alloy, will most probably affect the corrosion performance [7]. Mohamed et al. [7] in 1999 used dc electrochemical techniques to investigate the corrosion behaviour of crevice-containing and crevice-free Cast and Hot Isostatically Pressed (HIPed) Stellite 6 in 3% NaCl at ambient temperature. They concluded that Hot Isostatic Pressing (HIPing) could potentially improve the localised crevice and pitting corrosion resistance and related their findings to the crevice corrosion models developed by Oldfield and Sutton [8]. In a study by Kim and Kim [9], the corrosion resistance of PTA-welded surfaces was compared to spray-fused and open arc-welded surfaces. It was concluded that dilution effects, which change the composition due to mixing of the coating and the underlying substrate, are key issues in the corrosion resistance of welded layers and the PTA process in this respect was superior to the other two processes. + + +The compositional roots of contemporary cobalt-base superalloys stem from the early 1900s when patents covering the cobalt–chromium and cobalt–chromium–tungsten system were issued. Consequently, the Stellite alloys of E. Haynes became important industrial materials for cutlery, machine tools and wear-resistant hardfacing applications [1,2]. The cobalt–chromium–molybdenum casting alloy Vitallium was developed in the 1930s for dental prosthetics, and derivative HS-21 soon became an important material for turbocharger and gas turbine applications during the 1940s. Similarly, wrought cobalt–nickel–chromium alloy S816 was used extensively for both gas turbine blades and vanes during this period. Another key alloy, invented in about 1943 by R.H. ∗ Corresponding author. Present address: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. Tel.: +44 113 343 6812; fax: +44 113 242 4611. E-mail address: a.neville@leeds.ac.uk (A. Neville). 1 Present address: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. Thielemann, was cast cobalt–nickel–chromium–tungsten alloy X-40. This alloy is still used in gas turbine vanes and subsea drill bits, and it has served extensively as a model for newer generations of cobalt-base superalloys. Hot isostatic pressing (HIPing) is rapidly becoming an industry standard as a processing method. Due to increasingly complex engineering shape specifications, higher demands on quality and lowering costs, HIPing has matured to a stage where it is recognized universally and is used on an industrial scale. HIPing requires a high-pressure vessel and consists of applying high isostatic pressure, using an inert gas, to the surface of the piece being processed or on the surface of a can filled with powder. A resistance heater inside the pressure vessel provides the necessary heat for the treatment. The microstructures of Stellite alloys vary considerably with composition, manufacturing process and post treatment. They may either be in the form of hypoeutectic structure consisting of a Co-rich solid solution surrounded by eutectic carbides, or of the hypereutectic type containing large idiomorphic primary chromium-rich carbides and a eutectic [1] + +It is generally acknowledged that the susceptibility of passive metals to localised corrosion (including pitting) and the rate at which this corrosion process occurs are closely related to the ability of the passive film to resist breakdown and to repassivate once corrosion has initiated [2]. The chemical composition of the passive film, its structure, physical properties, coherence and thickness are of paramount importance in the nucleation and propagation of localised corrosion. Investigations into the composition and structure of passive oxide films on stainless steels and other related passive alloys are much more difficult than in the case of iron because the films are thinner, their chemical composition is complicated, and they cannot be reduced cathodically. A major part of the information available on composition and structure of passive films on stainless steels has been obtained with spectroscopic techniques, particularly X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES). Other methods such as ion scattering spectroscopy (ISS) and secondary ion mass spectrometry (SIMS) also provide valuable data [3]. + +In the chemical, petrochemical and pump industries, machine parts often work in conditions where erosion and corrosion processes, acting together, are the main failure mechanisms. The deleterious synergistic effect of the erosion removes either corrosion product or the passive layer that is protecting the underlying surface. When a passive layer is removed, the time taken for it to repassivate is an important consideration in the assessment of wear rates. The rate of repassivation determines the amount of charge that can transfer when the surface is activated by an erosion event (e.g. impact of sand). The rate of repassivation in relation to the frequency of impact is an important consideration in erosion–corrosion. On stainless steels [1] it was shown that higher amounts of key elements (chromium, molybdenum) can lead a faster repassivation during erosion impacts. ∗ Corresponding author. Tel.: +44 113 343 6812; fax: +44 113 242 4611. E-mail address: a.neville@leeds.ac.uk (A. Neville). Cobalt-based alloys have enjoyed extensive use in wearrelated engineering applications for well over 50 years because of their inherent high-strength, corrosion resistance and ability to retain hardness at elevated temperatures [2]. In recent years a concentrated effort has been made to understand the deformation characteristics of cobalt-based alloys exposed to erosion–corrosion environments in order to optimize those factors contributing to their erosion resistance [3–5]. Alloying cobalt with chromium and various quantities of carbon, tungsten and molybdenum produces a family of alloys which can have excellent resistance to corrosion and/or erosion. Understanding how microstructural changes, as a result of alloying, affect corrosion and erosion resistance is critical to optimising the alloy for a particular purpose. In cobalt-based alloys, the key element chromium is added in the range of 20–30 wt.% to improve corrosion and impart some measure of solid-solution strengthening. Where carbide precipitation strengthening is a desirable feature, chromium also plays a strong role through the formation of a series of varying chromium–carbon ratio carbides such as M7C3 and M23C6. Alloying elements like tungsten, molybdenum and 0043-1648/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2005.02.038 tantalum are added to cobalt for solid solution strengthening. If these metals are added in excess of their solubility, formation of carbides like MC and M6C is likely to occur. Shin et al. [6] investigated the effect of molybdenum on the microstructure and wear resistance properties of Stellite 6 hardfacing alloy. They showed that with an increase in molybdenum content, the M23C6 and M6C type carbides were formed instead of chromium-rich M7C3. They concluded that this microstructural change was responsible for the improvement of the mechanical properties such as hardness and wear resistance of molybdenum-modified Stellite 6 hardfacing alloy. Most cobalt-based alloys possess outstanding cavitation resistance compared to stainless steels which has been shown to be independent of the carbon content (hence hardness), and has been attributed by Crook [7] to crystallographic transformation, under stress, from the face centred cubic (fcc) to hexagonal close packed (hcp) structure by twinning. Heathcock and Ball [8] studied the cavitation resistance of a number of Stellite alloys, cemented carbides and surface-treated alloy steels and showed that in Stellite alloys the cobalt-rich solid solution, incorporating elements such as chromium, tungsten and molybdenum is highly resistant to erosion due to a rapid increase in the work-hardening rate and the strain to fracture which are caused by deformation twinning. Lee et al. [9] compared the liquid impact erosion resistance of 12 Cr steel with a Vickers hardness of 380 kg/mm2 (∼39 MPa) and Stellite 6B with a hardness value of 420 kg/mm2 (∼43 MPa). The liquid impact erosion resistance of Stellite 6B was at least six times greater than that of 12 Cr steel, implying that hardness is not the governing factor for liquid erosion. Stellite 6B also showed very different behaviour in liquid impact erosion in comparison with 12 Cr steel. They concluded that the superior erosion resistance of Stellite 6B results from the cobalt matrix whose deformation appeared mostly as mechanical twins and the material removal was more dominant in the hard carbide precipitates than in the ductile cobalt matrix. Wong-Kian [10] showed that Stellite coatings were advantageous for use in erosion–corrosion environments and can even function at relatively high temperatures. They reported that this is because wear resistance is promoted by the harder complex carbides of chromium and tungsten, while corrosion resistance is enhanced by the presence of cobalt in the matrix. + +Cobalt-base alloys are now progressively used in many industrial and other applications. This is basically due to their high-temperature mechanical strength and their corrosion resistance in many environments. Some categories of these alloys may be used as high-temperature structural materials, wear resistant materials in aggressive media or for orthopedic implants. The main alloying elements are usually Cr, MO, W and Ni. Additionally, wear resistant alloys normally contain relatively high levels of carbon (0.25 to 2.5 wt.%) needed for carbide formation, while alloys used for structural applications are normally low in carbon. Alloy Stellite-6 is a Co—Cr—W—C alloy which exhibits an outstanding oxidation and corrosion resistance, hightemperature strength as well as resistance to thermal fatigue. The wrought alloy is used in nuclear and other industrial engineering purposes [1 to 4]. In nuclear industry, Stellite-6 is one of the most popular alloys used in manufacturing control and safety valve components in pressurized water reactors (PWR). It has also been used for control shaft guide bushings in sodium cooled reactors (LMFBR). In chemical industry, the alloy is used in the form of weld overlay for catalytic reactor valves for various liquids to resist the effect of corrosive wear and for surfacing of combustion engine valves and steam turbine valves. Powder metallurgy (PIM) is a fabrication technology capable of producing reasonably complex designs at relatively high rates of production. Using P/M technology, segregation problems (normally associated with conventional casting techniques) are minimized, especially for small parts. The metallurgical characteristics of the end product are primarily developed during the sintering cycle [5, 6]. Powder metallurgy techniques have been applied for the production of cobalt-base alloys. Two basic P/M techniques, namely hot isostatic pressing (HIP) and wet powder pouring (WPP) have been used for production of alloy Stellite-6. Details of these processes are described elsewhere [7, 8]. + +Cobalt-base (Stellite) alloys have seen extensive use in wear environments mainly due to their high strength, corrosion resistance and hardness. Co-base superalloys rely primarily on carbides, formed in the Co matrix and at grain boundaries, for their strength and wear resistance. The distribution, size and shape of carbides depend on processing conditions. Solid solution strengthening of Co-base alloys is normally provided by tantalum, tungsten, molybdenum, chromium and niobium [1]. Since these elements are all carbide formers, their effectiveness in terms of solid solution strengthening is dependent on the C content of the alloy. Stellite 6 with nominal composition Co–28Cr–4.5W–1.2C (wt%) was the first Stellite alloy developed in the early 1900s by Elwood Haynes. In recent years there have been investigations into the effect of alloying elements additions on the microstructure and mechanical properties of Stellite 6 [2]. Improved hardness through formation of intermetallic compounds and mixed carbides was achieved in both cases. It has been shown that adding W and Mo influences corrosion behaviour by stabilizing the face-centred cubic (fcc) phase [1]. ∗ Corresponding author. Tel.: +39 011 0904641; fax: +39 0110904699. E-mail address: francesco.rosalbino@polito.it (F. Rosalbino). Because Stellite alloys are often used to combat wear, there have been numerous studies into surface engineering strategies to functionalize the surface for a specific application. These have included plasma transferred arc (PTA) welding [3], laser surface melting [4] and plasma diffusion treatments [5] all involving Stellite alloys. Application of Co-base superalloys was traditionally most prevalent in the nuclear industry in the 1960s and 1970s and, for this reason, much research into corrosion of Stellite focused on conditions relating to nuclear power applications such as simulated PWR primary heat transfer conditions [6,7]. Currently, use of Stellite alloys has extended into various industrial sectors (e.g. pulp and paper processing, oil and gas processing, pharmaceuticals, chemical processing) and the need for improved information regarding corrosion (and often tribo-corrosion) of Stellite has increased. It has been recognized that processing changes, which affect the microstructure of Stellite alloys, most affect corrosion performance [8]. Hot isostatic pressing (HIPing) is a thermo-mechanical process [9] in which components or a contained powder is subjected to simultaneous applications of heat and high pressure in an inert medium. HIPing removes internal void cavities thus consolidating the structure making it homogenous, segregation free, dense, nearnet shape and requiring little or no machining. diff --git a/thesis_original.org b/thesis_original.org new file mode 100644 index 0000000..4564e87 --- /dev/null +++ b/thesis_original.org @@ -0,0 +1,1650 @@ +#+TITLE: Cavitation Erosion in Blended Stellite Alloys +#+AUTHOR: Vishakh Pradeep Kumar + + + + + +Since the 1930s, investigations on cavitation erosion have sought to quantiy the cavitation erosion resistance of materials, establish correlations with mechanical properties (yield & tensile strength, strain energy, elastic modulus, and hardness), and formulate phenomenological models that describe the cavitation erosion process. + +Materials grouped by similar microstructure show a trend of increasing cavitation erosion resistance with increasing hardness, although this trend does not necessarily hold across disparate materials \cite{HANDBOOKCAVITATIONDAMAGE}. In addition to the original hardness of the material, cavitation erosion resistance appears to be resistant to the ability of a metal to be work hardened \cite{HANDBOOKCAVITATIONDAMAGE}. + + + +. +Strain energy and its evolution to erosion strength because of how stellite shows phase transformation effects. + +Steller \cite{} noted the poor agreement beween + +Steller [72,73] observed that often there was poor agreement between cavitation resistance of materials measured in different types of test rigs and this proved to be a stumbling block in the prediction of material performance in the prototype. + + + + +* Grain size + +ASTM E112 +Heyn Lineal Interceot Procedure + + + + +* Strain Energy + +As cavitation erosion is caused by consecutive bubble impacts over a duration of time, similar to fatigue phenomenon, with accumulte86d strain energy is natural tothe ability of the material to + + +# Ultimate resilience (also called unit rupture work) is the amount of energy absorbed per unit volume of material as it is taken from zero load to rupture, in tension. In the context of a tensile stress-strain curve, ultimate resilience is the area under the curve. + + +Thiruvengadum defines erosion strength as the energy absorbed per unit volume of material up to fracture under the action of the erosive force in various environments \cite{thiruvengadamConceptErosionStrength1967}. + +| Thiruvengadam, Thiruvengadam and Waring [65,66] + +Thiruvengadum \cite{thiruvengadamUnifiedTheoryCavitation1963, thiruvengadamMechanicalPropertiesMetals1966} + +Steady state erosion rate \propto \frac{1}{SE} + + +CavitationErosionBehaviourSteelPlateScroll + + + + + +* Timeline latex +Use for cavitation curves models +https://github.com/MLNLP-World/Paper-Picture-Writing-Code/blob/main/latex/imgs/category/timeline.png + +* TODO Find out the SEM guy at BITS Pilani + +https://www.facebook.com/bitsdubai/posts/-we-are-pleased-to-announce-the-inauguration-of-the-newly-established-advanced-c/291636303624927/ + +* TODO + +Need to get ASTM G32 buttons made by that Chinese CNC dude Tulika showed you + + +* Project Proposal + +** Abstract + + + +Cavitation erosion process is a multifaceted phenomenon that depends not only on the strength characteristics of cavitating bubbles but also on the erosion resistance of materials to the cavitation energy imparted upon them. The loss of material due to cavitation leads to degradation in performance + + +The aim of this MSc project is to investigate the resistance of blended stellite alloys to cavitation erosion. The cavitation phenomena is simulated by ultrasonic vibrating probes, or sonicators, located at fixed gap from the material. + +The synergistic effect existing between cavitation erosion and corrosion erosion is investigated with the help of in-situ electrochemical measurements of corrosion. + + +# Describe the apparatus +Experiments are to be conducted using an ultrasonic vibratory horn, with fixed frequency 20 kHz and variable peak to peak amplitude. + +# Describe the need for scanning electron microscopy +Scanning electron microscopy is to be used to characterize the microstructural characteristics of the cavitated sample surfaces, as well as cross sections of the surface directly underneath cavitation. + + + +** Introduction + + +# Context +# How well was the project placed in the context of previous work? +# In your case, you really need to underscore Rehan's work on stellites and Ahmed's work on cavitation erosion + + +# Describe why there is a need to look from both the fluid and solid perspective +Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics \cite{Franc2004265}. + +# Hydrodynamic POV +From a hydrodynamic standpoint, cavitation erosion results from the formation of and subsequent collapse of vapor bubbles within a fluid medium, due to the local pressure reaching the saturated vapor pressure (due to pressure decrease (cavitation) or temperature increase (boiling)). When these bubbles implode, they emit heat, shockwaves, and high-speed microjets that can impact adjacent solid surfaces, leading to damage to the surface and removal of material due to the accumulation of damage following numerous cavitation events. + +The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery \cite{GEVARI2020115065}. + +# Now do the materials POV +The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest. The resulting reduction of performance & service life and the increased maintenance and repair costs motivate research into understanding how materials respond to the impact of a cavitating material. Cavitation erosion is a major problem in hydroelectric power plants \cite{Romo201216}, Francis turbines \cite{Kumar2024}, nuclear power plant valves \cite{Kim200685,Gao2024}, condensate and boiler feedwater pumps \cite{20221xix}, marine propellers \cite{Usta2023}, liquid-lubricated journal bearings \cite{Cheng2023}, pipline reducers \cite{Zheng2022, Chen201442, Mokrane2019}. + +# The commercial wear resistant Stellite alloys are derived from the Co–Cr–W–C family first investigated by Elwood Haynes in early 1900s [1]. + +# Stellites +Stellite alloys consist of a cobalt (Co) matrix with solid-solution strengthening of chromium (Cr) and tungsten(W)/moblybdenum(Mo), and hard carbid phases (Co, Cr, W, and/or Mo carbides) \cite{Shin2003117, Crook1992766, Desai198489, Youdelis1983379}. The matrix provides execelent high-temperature performance, while the carbides provide strength, wear resistance and resistance to crack propagation \cite{Ahmed2021, Crook199427}. + +# Applications +Stellites are typically used for wear-resistant surfaces in lubrication-starved, high temperature or corrosive environments \cite{Zhang20153579, Ahmed2023, Ahmed20138, Frenk199481, Song1997291}, such as in the nuclear industry \cite{McIntyre1979105, Xu2024, Gao2024}, oil & gas \cite{Teles2024, Sotoodeh2023929}, marine \cite{Song2019}, power generation \cite{Ding201797}, and aerospace industries \cite{Ashworth1999243}. Hot Isostatic Pressing (HIP) consolidation of Stellite alloys offers significant technological advantages for components operating in aggressive wear environments \cite{Ahmed20138, Ahmed201470, Ashworth1999243, Yu20071385}. Yu et al \cite{Yu2007586, Yu20091} note that HIP consolidation results in superior impact and fatigue resistance over cast alloys. + +# Why are stellites OP at cavitation? +# Stellites have good CE resistance due to the low stacking fault energy of the cobalt fcc phase, which favors planar slip dislocations and increases the number of cycles that leads to fatigue failure. + +# Understanding the matrix phase +Understanding the cobalt phase is crucial for studying structural changes in Co-based alloys widely used in industry. Cobalt and Co-Cr-Mo alloys undergo thermally induced phase transformation from the high temperature face-centered cubic (fcc) $\gamma$ phase to low temperature hexagonal close-packed (hcp) $\epsilon$ phase at 700 K and strain induced fcc-hcp transition through maretensitic-type mechanism (partial movement of dislocations) \cite{HUANG2023106170}. At ambient conditions, the metastable FCC retained phase in stellites can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}; the metastable fcc cobalt phase in stellite alloys \cite{Rajan19821161} absorbs a large part of imparted energy under the mechanical loading of cavitation erosion. The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) \cite{Tawancy1986337}. Solid-solution strengthening leads to increase of the fcc cobalt matrix strength (due to distortion of the atomic lattice with the additino of elements of different atomic radiuses), decrease of low stacking fault energy \cite{Tawancy1986337} due to the adjusted electronic structure of the metallic lattice, and inhibition of dislocation cross slip. Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. The addition of nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W), stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm), although Cr and W increases hot corrosion resistance \cite{Vacchieri20171100, Tawancy1986337}. +# Maybe get the size of atoms and show the mismatch? + + +# Let's now move into the carbides portion. +In addition to solid-solution strengthening, the precipitation of carbides allows stellites to endure mechanical and thermal stresses at high temperature. \cite{Gui20171271,osti_4809456} + + + + +# Novelty +# How well was the novelty of the project expressed? + +To date, academic research pertaining to cavitation erosion specifically on HIP'd stellite alloys appears to be absent from the existing literature. + + +# Novelty - Me jerking off to the novelty of my thesis +Given the detrimental influence of voids and defects on cavitation erosion, the lack of academic investigation into cavitation erosion on HIP (Hot Isostatic Pressing) stellite alloys, underscores the need for further exploration. Moreover, the complexity introduced by blended stellite alloys in the context of cavitation erosion in corrosive enironments adds another layer of intrigue to this research endeavor. By analyzing the interactions between alloy composition, microstructure, and cavitation erosion behavior, this thesis aims to fill a critical gap in the current understanding of material performance under cavitation erosion conditions. + + + + + +# As-cast cobalt-base superalloys consist of a variety of carbides, which mainly includes coarse primary M7C3, M23C6 and MC + + + + +While solid-solution strengthening is a necessary factor in stellites, the most important strengthening mechanism in current alloys is the precipitation of carbides. + +Cr guarantees hot corrosion resistance and forms M23C6 carbides, while form MC carbides +\cite{Vacchieri20171100}. + + + + + + +Cavitation erosion of Stellites is material removal through crack propagation through the cobalt matrix through the matrix-carbide interface \cite{Szala2021}, making the solid solution strengthening of the matrix a critical parameter \cite{Heathcock1981597}. + +\cite{Zhang2021} find that high hardness + +Therefore, the negative effect of porosity is weaker than the positive effect of grain refinement, low dilution ratio and high hardness on cavitation performance. Consequently, SLD coating has better cavitation resistance than LC coating. © 2020 Elsevier B.V.}, + + +Liu et al \cite{Liu2022} find that Stellite 21 has superior CE resistance in seawater due to the formation of compact Cr oxides on erosion pits. + + + + + + HIPed Stellite 6 wear behaviour relies on the plastic deformation of cobalt matrix, starting at Cr7C3/matrix interfaces. + + Once the Cr7C3 particles lose from the matrix restrain, they debond from matrix and are removed from the material. + + Carbides detachment creates cavitation pits which initiate cracks propagation through cobalt matrix, leading to further detachment of chunks of material. + + + +# Motivation +# Scope +# Aims + + + + +** Aims and Objectives +# Were the aims of the project clearly expressed? +# Were they specific and measurable? +# Were they realistic? +# Were adequate timescales referred to? + +** Methodology + +Cavitation testing is to be carrier out according to ASTM G32 indirect method, with an ultrasonic titanium tip operating at a frequency of 20kHz and peak to peak amplitude of 50 um. + +- The time period for each test was 1 h, except the polarization test, in fresh batch of mediums. +- The standoff distance between the sample and the ultrasonic transducer was kept constant at 2 mm. +- The temperature of the water is to be maintained at room temperature of 22 °C ± 0.5 °C +- The pH of the water is to be maintained at a pH range of 7.5 - 8.5. + +test arrangement. + + +*** Work Packages +Were tangible work packages (activities and steps) defined that would be used to achieve the aims of the project? + + +Research phase Objectives Deadline + +- Background research and literature review + - Meet with supervisor for initial discussion + - Read and analyze relevant literature + - Use new knowledge to refine research questions + - Develop theoretical framework +- Research design planning + Design questionnaires + Identify channels for recruiting participants + Finalize sampling methods and data analysis methods +- Data collection and preparation + Recruit participants and send out questionnaires + Conduct semi-structured interviews with selected participants + Transcribe and code interviews + Clean data +- Data analysis + Statistically analyze survey data + Conduct thematic analysis of interview transcripts + Draft results and discussion chapters +- Writing + Complete a full thesis draft + Meet with supervisor to discuss feedback and revisions +- Revision + Complete 2nd draft based on feedback + Get supervisor approval for final draft + Proofread + Print and bind final work + Submit + + + + +*** Resources +Were the resources needed for the project well-defined? Were they in place already? Was there a statement of the planning needed to put the necessary resources in place? + +*** Associated risks +# Were the risks which might affect the success of the project defined? +# Were measures suggested to mitigate these? + +Main risk about the dissertation is the time allowed. Indeed, despite of having some basic knowledge in solid mechanics, I’ll need to really understand in depth the physics behind the phenomenon of vibration, to get a complete frame of work principle of BWTs. Moreover, time of simulations is not compressible and based on previous experiences, including SpecEng1 project, 3D simulations can take a long time depending on needed precision. Also, even if I used ANSYS CFX by the past, the software is so complete that it might be long to master it. The creation of the Gantt chart will help managing my time, allocating enough time for each subsidiary objective. + +**** Technical Risks + +# If your project is based around a technology, technical risks relate to specific challenges to delivering that technology and making it work as expected. + +Technical risk pertains to the development and manufacturing of the experimental rig, with focus on the ability of the system to achieve the performance required to meet technical specifications and stakeholder expectations. + +- Experimental setup complexity + Experimental setup could pose unexpected issues due to lack of planning + + Risk mitigation strategies: + + - Detailed Planning and Design in CAD + The rig is to be designed in CAD to ensure all subsystems meet spatial, power, and I/O requirements. + + - Expert Consultation & Review + The rig design is to be reviewed by supervisor and other expereinced researchers & engineers. Feedback is to be recorded and designed altered to alleviate concerns. Identified people for review are: + - Dr Rehan Ahmed + - Dr Mohammed Al-Musleh + - Muhsin Aykapaddatu + +- Functionality/performance is not as expected or to specification + - Pilot testing of experimental rig to ASTM G32 standard + Validation of rig using the known materials and comparing results to existing data. + + - Documenting Procedures and Troubleshooting Protocols + Maintaining documentation of all components used as reference, in addition to developing a Standard Operating Procedure (SOP) outlining each step of the experimental procedure according to the ASTM G32 standard. + + - Modular Design & Redundancies + The experimental rig design is modularized, in order to allow for easy modificatino and adjustment of components as needed. Spare parts are to be readily available, either in nearby storage or purchasable through local vendors; rig design is to allow for rapid replacement or repair if necessary. + +- Noise exposure +- Chemical Hazards +- Instrumentation Failure + +**** Data Acquisition and Analysis + +Managing and analyzing large volumes of experimental data, including high-speed imaging and erosion measurements, can be daunting. Ensuring the reliability, accuracy, and consistency of data collection and analysis methods is essential for drawing valid conclusions. + +***** Pre-Experiment Preparation: +Develop a detailed data acquisition plan outlining the parameters to be measured, the sampling frequency, and the duration of data collection. +Ensure all data acquisition equipment is properly calibrated and validated before starting experiments. + +***** Quality Control Measures: +Implement rigorous quality control measures during data acquisition to minimize errors and ensure data accuracy. +Conduct regular checks to verify the consistency and reliability of measurements throughout the experiment. + +***** Data Management Protocols: +Establish clear protocols for data management, including organization, storage, and backup procedures to prevent loss or corruption of data. +Use standardized file naming conventions and metadata documentation to facilitate data retrieval and analysis. + +***** Real-Time Monitoring: +Implement real-time monitoring of data acquisition systems to promptly identify and address any issues or anomalies during experiments. +Set up alerts or alarms for out-of-range measurements to prevent data loss or invalid results. + +***** Data Validation and Verification: +Validate acquired data by comparing it with theoretical predictions, empirical models, or data from previous studies. +Perform sensitivity analyses and cross-checks to verify the consistency and reliability of results obtained from different measurement techniques or instruments. + +***** Statistical Analysis Techniques: +Apply appropriate statistical analysis techniques to identify trends, correlations, and outliers in the acquired data. +Utilize statistical software packages for robust analysis and interpretation of experimental results. + +***** Error Propagation Analysis: +Conduct error propagation analysis to assess the impact of measurement uncertainties on the final results. +Quantify uncertainties associated with each measurement parameter and propagate them through the analysis to determine their effect on the overall conclusions. + +***** Peer Review and Collaboration: +Seek feedback and peer review from colleagues, advisors, or experts in the field to validate the accuracy and reliability of data analysis methods and results. +Collaborate with researchers with expertise in data analysis techniques to enhance the robustness and comprehensiveness of your analysis. + +***** Documentation and Reproducibility: +Document all data acquisition and analysis procedures in detail, including software codes, algorithms, and assumptions used. +Ensure transparency and reproducibility of data analysis by providing comprehensive documentation and making raw data and analysis scripts available to others. + + +** Other stuff + + +Issues with integration with other technologies/hardware/software within the project +Failures under test or demonstration conditions +Failure to meet required standards or legislation. + +Implementation Risks +To some extent these are inter-related to all the risks you identify, but essentially relate to project management issues during delivery of your project. They might include: +Substantial delays in the tasks +Overspend or other financial issues +Partners leaving, not contributing to the project as intended, or going in to liquidation +Legal issues, such as data protection issues or IP infringement. + + +Societal & Commercialization Risks are outside the scope of this research proposal. + + + + + + + +*** Expected outcomes +Was the anticipated result of the project clearly defined? +Were sensible interim milestones identified? + + +*** Resources needed + +*** Risks anticipated + + +*** Beneficiaries of work + +# Was it made clear who would benefit from the work carried out in the project + +# Contribution to knowledge + +To finish your proposal on a strong note, explore the potential implications of your research for your field. +Emphasize again what you aim to contribute and why it matters. +For example, your results might have implications for: +Improving best practices for cavitation erosion research at Heriot-Watt University +Comparing models that predict erosion resistance +Challenging popular or scientific beliefs +Creating a basis for future research + + +* Literature review + + +# Describe why there is a need to look from both the fluid and solid perspective +Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics \cite{Franc2004265}. When components are exposed to sustained cavitation erosion, the component surface is degraded and material is progressively lost. Cavitation erosion is a major problem in hydroelectric power plants \cite{Romo201216}, Francis turbines \cite{Kumar2024}, nuclear power plant valves \cite{Kim200685,Gao2024}, condensate and boiler feedwater pumps \cite{20221xix}, marine propellers \cite{Usta2023}, liquid-lubricated journal bearings \cite{Cheng2023}, pipline reducers \cite{Zheng2022, Chen201442, Mokrane2019}. + +# Hydrodynamic POV +From a hydrodynamic standpoint, cavitation erosion results from the formation of and subsequent collapse of vapor bubbles within a fluid medium, due to the local pressure reaching the saturated vapor pressure (due to pressure decrease (cavitation) or temperature increase (boiling)). When these bubbles implode, they emit heat, shockwaves, and high-speed microjets that can impact adjacent solid surfaces, leading to damage to the surface and removal of material due to the accumulation of damage following numerous cavitation events. The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery \cite{GEVARI2020115065}. Impurities in the fluid, such as solid particles and nanobubbles with a radius of 500nm can significantly reduce the cavitation threshold leading to increased cavitation intensity. When these bubbles collapse near walls, the concentration of energy on very small areas of the wall result in high stress levels on the wall. + +# Let's hyperfocus on the wall for a bit +# In the case of a nucleus situated in the middle of a very confined domain # between two parallel walls, growth is fastest in the directions parallel to the wall. During the subsequent collapse phase, the reverse occurs: there is a rapid equatorial contraction and the bubble takes the shape of an hourglass, before splitting into two symmetric bubbles. Each one then develops a re-entrant jet directed towards the nearest wall. + +# The notion that the aggressiveness of cavitation could be +# assessed through a consideration of energy conversion was +# already acknowledged by Hammitt + +# Now do the materials POV +The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest. The resulting reduction of performance & service life and the increased maintenance and repair costs motivate research into understanding how materials respond to the impact of a cavitating material. + + +# The commercial wear resistant Stellite alloys are derived from the Co–Cr–W–C family first investigated by Elwood Haynes in early 1900s [1]. + +# Stellites + +Stellite alloys belong to the cobalt-chromium family, with the addition of tungsten or molybdenum as the main alloying elements. +The matrix in stellite alloys consist of cobalt (Co) with solid-solution strengthening of a substantial amount of chromium (Cr) and tungsten(W)/moblybdenum(Mo), resulting in high hardness & strength at high temperature, with carbide precipitations (Co, Cr, W, and/or Mo carbides) adding strength and wear resistance \cite{Shin2003117, Crook1992766, Desai198489, Youdelis1983379, Ahmed2021, Crook199427}. + +# Understanding the matrix phase +# Understanding the cobalt phase is crucial for studying structural changes in Co-based alloys widely used in industry. +Cobalt and Co-Cr alloys undergo thermally induced phase transformation from the high temperature face-centered cubic (fcc) $\gamma$ phase to low temperature hexagonal close-packed (hcp) $\epsilon$ phase at 700 K and strain induced fcc-hcp transition through maretensitic-type mechanism (partial movement of dislocations) +\cite{HUANG2023106170}. +At ambient conditions, the metastable FCC retained phase in stellites can be transformed into HCP phase by mechanical loading, although any HCP phase is completely transformed into a FCC phase between 673 K and 743 K \cite{DUBOS2020128812}; the metastable fcc cobalt phase in stellite alloys \cite{Rajan19821161} absorbs a large part of imparted energy under the mechanical loading of cavitation erosion. + +The fcc to hcp transition is related to the very low stacking fault energy of the fcc structure (7 mJ/m2) \cite{Tawancy1986337}. + +# Let's talk about the addition of other elements +Solid-solution strengthening leads to increase of the fcc cobalt matrix strength (due to distortion of the atomic lattice with the addition of elements of different atomic radii), and decrease of low stacking fault energy \cite{Tawancy1986337} due to the adjusted electronic structure of the metallic lattice. Dislocation motion in stellites is discouraged by solute atoms of Mo and W, due to the large atomic sizes. Given that dislocation cross slip is the main deformation mode in imperfect crystals at elevated temperature, as dislocation slip is a diffusion process that is enhanced at high temperature, this leads to high temperature stability \cite{LIU2022294}. In addition, nickel (Ni), iron (Fe), and carbon (C) stabilize the fcc structure of cobalt (a = 0.35 nm), while chromium (Cr) and tungsten (W), stabilize the hcp structure (a = 0.25 nm and c = 0.41 nm) \cite{Vacchieri20171100, Tawancy1986337}. + +# Maybe get the size of atoms and show the mismatch? + +The amount and types of carbides dispersed in the stellite matrix are primarily determined by the carbon content, with higher carbon content encouraging carbides with higher C/M ratios, while the size of carbides is determined by the cooling rate. Carbon content can be used to distinguish between different Stellite alloys: high-carbon Stellites designed for high wear resistance, abrasion, & severe galling, medium-carbon (0.5 - 1.6% wt) Stellites used for high temperature service, and low-carbon (<0.5% wt) stellites used primarily for corrosion resistance, cavitation, & sliding wear \cite{kapoor2013microstructure}. Low-carbon stellites depend primarily of solid-solution strengthening for their mechanical properties. As the carbon content increases, the W/Mo content is usually also increased to prevent depletion of Cr from matrix solid solution strengthening. Chromium is the predominant carbide former, with M7C3 and M23C6 phases, in addition to providing corrosion resistance and strength to the stellite matrix. Difference between the M7C3 and M23C6 phases is not readily visible under SEM. In tungsten-containing alloys, carbides of type M7C3 and M6C are formed in addition to the matrix. Ahmed et al report on the identification of intermetallic Co3W and Co7W6 phases through XRD, although these phases are not identified in SEM observations. + + +# Insert table of stellite compositions here + +# Why are stellites OP at cavitation? +# Stellites have good CE resistance due to the low stacking fault energy of the cobalt fcc phase, which favors planar slip dislocations and increases the number of cycles that leads to fatigue failure. + +# Applications +Stellites are typically used for wear-resistant surfaces in lubrication-starved, high temperature or corrosive environments \cite{Zhang20153579, Ahmed2023, Ahmed20138, Frenk199481, Song1997291}, such as in the nuclear industry \cite{McIntyre1979105, Xu2024, Gao2024}, oil & gas \cite{Teles2024, Sotoodeh2023929}, marine \cite{Song2019}, power generation \cite{Ding201797}, and aerospace industries \cite{Ashworth1999243}. Hot Isostatic Pressing (HIP) consolidation of Stellite alloys offers significant technological advantages for components operating in aggressive wear environments \cite{Ahmed20138, Ahmed201470, Ashworth1999243, Yu20071385}. Yu et al \cite{Yu2007586, Yu20091} note that HIP consolidation results in superior impact and fatigue resistance over cast alloys. + + + +# The heck is a blended stellite alloys +A blended stellite alloy is formed by hot isostatic pressing of a mixture of two stellite powders. The powders are created through gas atomization, in which a stream of liquid stellite alloy is disrupted and atomized into tiny molten droplets by a high-pressure inert gas flow. The free-falling molten droplets rapidly solidify into spherical particles before being collected, forming high quality stellite powders with controllable size. The rapid cooling of the powder during atomization leads to reduced precipitation of carbides and supersaturation of the metallic matrix with other elements, as seen in the reduced proportion of carbide phases detected in the XRD performed on powders, compared to XRD of HIP'd samples. The mixing of powders is conducted in a powder hopper that ensures uniform distribution of powder mixtures. The HIP treatment was conducted at a temperature of 1200 C and a pressure of 100 MPa for a duration of 4 hours, resulting in full dense blended stellite alloys. During the HIP'ing process, carbides are precipitated, in addition to reduction of supersaturation of the matrix. + + +Depending on the composition of the stellite powders used, the blended alloys could possess uniform microstructure or regions that are similar to the constituent powders. This is due to the different diffusion rates of the added elements - carbon diffuses through the blended alloys while tungsten cannot diffuse due to its high atomic radius. + +# Blended stellitttte alloys +# Mechanical alloying has been defined as a process that involves repeated cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. Mechanical alloying is a solid-state powder processing process that combines mixtures of powders in a high-energy ball mill to induce the creation of a homogeneous alloy through repeated cold welding, fracturing, and rewelding. Every time two balls collide, some amount of powder is hit, with the particles plastically deformed and welded together, resulting in composite particles. The process continues until all composite particles contain the starting ingredients in the proportion they were mixed together. As the process does not involve the phase transformation of the constituent powders, mechanical alloying allows for the synthesis of novel blends with composite phases that would be difficult or impossible to produce via traditional casting techniques. The composite particles can be consolidated through sintering or hot isostatic processing to produce Compositionally Complex Materials. + + + + + + + + +# Let's describe the ultrasonic cavitation setup and go deeper +# Why is thin layer stuff so important? +The ASTM G32 standard defines the study of cavitation performance of materials by placing an ultrasonic sonotrode above a stationary specimen, forming a thin liquid layer between the two solid walls. the sonotrode horn emits an acoustic wave into the fluid and causes cavitation when the pressure amplitude is sufficiently high. Due to the reflection and superposition of ultrasound in the thin liquid layer, the intensity of cavitating bubbles is increased, leading to accelerated cavitation erosion. + +#+CAPTION: Parameters defined by ASTM G32 +| Parameter | Value | +|------------------------+---------| +| Frequency | 20 kHz | +| Peak-to-peak amplitude | 50 um | +| Gap | 0.5 mm | +| Horn diameter | 15.9 mm | + +Endo et al \cite{Endo1967229} found that the extent of damage depends upon the thickness of the thin liquid layer, Kikuchi et al \cite{Kikuchi1985211} find that the extent of damage is a function of the reciprocal of the thickness of the liquid layer. For thicknesses $h < 0.5mm$, numerous bubbles coalese into several large bubble clusters in contact with the horn tip and the staionary specimen, while for thicknesses $h > 0.5mm$, the numerous bubbles produced are isolated \cite{Me-Bar1996741,Abouel-Kasem201221702, Wu201775}. + + + + + + + + +# Why is controlling temperature so important? + +The test water temperature affects the degree of cavitation erosion \cite{Singer1979147, Ahmed1998119}, with mass loss rate initially increasing with increase in temperature, peaking at an optimum temperature $T_m$, then decreasing with further increase in temperature \cite{Peng2020}, with bulk liquid temperatures above 50 C not altering erosion rate significantly \cite{Singer1979147, Nagalingam20182883}. + + +However, it must be noted that the temperature of the liquid film between the ultrasonic tip and sample rises rapidly, regardless of the bulk liquid temperature \cite{Endo1967229, Abouel-Kasem201221702}, with maximum erosion rates observed with film temperatures at temperatures 30-35 C \cite{Singer1979147, Priyadarshi2023}. + + + +Because the test water temperature markedly affects the degree +of erosion, impact pressure, and the number of bubbles as it is +observed by Ahmed + + title = {Investigation of the temperature effects on induced impact pressure and cavitation erosion}, + + + + +# Describe the experimental rig stuff + +Previous results of operation of the stationary specimen method +indicated that the minimum local pressure on the specimen, which +corresponds to the effective cavitation number, depends as +expected on several geometrical and operating parameters. These +parameters include the distance, h, between the stationary speci- +men and the horn-tip surfaces, the driving frequency of the horn, +and/or the amplitude of oscillation. + + + +# Let's talk about seawater, shall we + +In seawater (and other corrosive media), the coupling of corrosion and cavitation erosion can cause significant material damage with complex, synergistic mechanisms + +# Show how Fe coatings perform worse in seawater while Co coatings perform better, somehow + + + +# Cavitation erosion behaviour + +The cavitation erosion rate depends on the duration under cavitation, even when all test parameters are kept constant. with distinct stages: the incubation stage (with little material loss), acceleration stage, deceleration stage, and constant rate stage (with the rate of material erosion reaching a steady-state value). + + +The incubation stage + +Generally, cavitation erosion over time involves two stages, namely, the incubation stage (with little material loss, possibly due to the accumulation of internal stresses) and the erosion stage (with the rate of material erosion reaching a steady-state value). + + +Impact fracture is the dominating factor during the incubation period, with fatigue fracture being the dominant mechanism during the subsequent stages. \cite{HATTORI2001839} + + +* Introduction to Cavitation Erosion + +# Describe why there is a need to look from both the fluid and solid perspective +Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics. [cite:@Franc2004265] + +# Now go into the hydrodynamic point +From a hydrodynamic standpoint, vapor bubbles arise when local pressures within a fluid medium reduce to saturated vapor pressure, due to pressure decrease (cavitation) or temperature increase (boiling). +Mechanisms facilitating such pressure differentials include the propagation of ultrasonic waves and hydrodynamic pressure differentials induced by geometric constraints or the rotational dynamics of turbomachinery. +The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery. [cite:@GEVARI2020115065] +Moreover, impurities within the fluid, such as solid particles and nanobubbles with a radius of 500 nm, can significantly reduce the cavitation pressure threshold, amplifying the overall cavitation intensity. The subsequent collapse of these bubbles near solid boundaries, the resulting concentration of energy on very small areas of the wall result in high stress levels on the wall. + + +# Now do the materials point +The resultant stress levels, which range from 100 - 1000 MPa, can surpass material resistance thresholds, including yield strength, ultimate strength, or fatigue limit, leading to material removal from the surface and subsequent degradation of industrial sysytems. The high strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. The plastic deformation results in progressive hardening, crack propagation, and local fracture and removal of material, with the damage being a function of intensity and frequency of vapor bubble collapse. The selection of more resistent materials requires investigation of material response to cavitation stresses, with the mechanism of erosion being of particular interest. + +# What is affected by cavitation +Cavitation can occur in hydraulic systems (pumps, injector ports, high temperature liquid flows), marine propellers, and turbomachinery (steam turbines), and liquid metal systems (nuclear reactors, and metallurgical processes), with detrimental effect. + +# Put the below in a table +# Many metals and alloys have been investigated under cavitation erosion conditions; examples are: AI-based alloys, 11-13 Cu-based alloys, 14,15Ti-based alloys,16,17 cast irons,18,19 stainless steels,20-22 Co and Ni super- alloys,23-25 cemented carbides,24,26 non-metallic materials,27,28 composites,29,30 ceramics,31,32 and concrete and cements.33-35 + + +#+BEGIN_COMMENT +Imagine we've got two main ways things change their phase: +boiling, which is like turning up the heat until water decides it's too hot and wants to become steam; +and cavitation, which is more like giving water so much room to breathe that it gets dizzy and starts forming bubbles. + +Now, whether we're heating things up or letting the pressure down, the secret that lets this change happen is when the pressure around our water whispers, "It's time," by hitting the saturated vapor pressure. +So, in a nutshell, it's all about hitting that sweet spot where the water feels just right to jump into its next costume, be it vapor or bubbles. + +To make cavitation happen — think of it as getting water to the point where it starts popping bubbles — you can use sound waves that travel through the fluid, making the pressure go down. + +Also, if you mess with the path the fluid takes, like squeezing it through tight spots or whirling it around in pumps and propellers, that can also drop the pressure just right. It's like setting up an obstacle course for the fluid; the hurdles and twists help create those bubble-making low-pressure zones. +#+END_COMMENT + +#+BEGIN_COMMENT +# Why is cavitation so bad? +# Near-wall collapses of vapour bubbles lead to material fatigue and erosive damage. + +# # We can model the flow as inviscid! Go easier simulations +# The compressible wave propagation in cavitation is inertia driven; we can assume that viscous effects are negligible. Because the driving effects behind cavitation erosion are inertia driven (compressible wave propagation), we assume that viscous effects are negligible and apply the compressible Euler equation for mass and momentum conservation. + +# Distinguish between cavitation and boiling, for the new kids on the block. +# Cavitation is the process of nucleation in a liquid when the pressure falls below the vapor pressure, while boiling is the process of nucleation that occurs when the temperature is raised above the saturated vapor/liquid temperature. + +# Describe the vapor and gas stage +# The first and most obvious difference between the saturated liquid and saturated vapor states is that the density of the liquid remains relatively constant and similar to that of the solid except close to the critical point. On the other hand the density of the vapor is different by at least 2 and up to 5 or more orders of magnitude, changing radically with temperature + +#+END_COMMENT + + + + + + + + +# Describe the sonotrode setup +An ultrasonic horn (hereafter referred to as sonotrode) oscillates with a frequency of 20 kHz and a peak to peak amplitude of 50 um above a counter sample, with a gap width of 0.5mm. + +# Describe the simulation case +The domain is rotationally symmetric, leading to the use of a 90 degree segment being modelled to reduce computational effort. As cavitation is three-dimensional and non-periodic, the symmetry walls are modelled as periodic boundaries. + +# Grid independence study for fluids +As indicator for grid sensitivity study, we choose the vapor volume fraction integrated over the computational domain, as it describes the cavitating flow. + + +# Why a shadowgraph +Need to observe the cavitation bubbles being formed. + + + + + + + +cavitation erosion resistance of Stellite 6 coatings has also been the object of interest in several works: + + + + + + + +* Cavitation Description + +# Describe why there is a need to look from both the fluid and solid perspective +Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics [cite:@Franc2004265]. When components are exposed to sustained cavitation, the surface is degraded and material is progressively lost. + +# List of applications +# Who are our stakeholders, why should we care? +Cavitation erosion is a major problem in hydroelectric power plants [cite:@Romo201216], Francis turbines [cite:@Kumar2024], nuclear power plant valves [cite:@Kim200685][cite:@Gao2024], condensate and boiler feedwater pumps [cite:@20221xix], +marine propellers [cite:@Usta2023], liquid-lubricated journal bearings [cite:@Cheng2023], pipline reducers [cite:@Zheng2022] [cite:@Chen201442] [cite:@Mokrane2019]. + +# Now go into the hydrodynamic point +From a hydrodynamic viewpoint, vapor bubbles are produced when the local pressure in a originally liquid fluid reaches the saturated vapor pressure, due to cavitation (presure decrease) or boiling (temperature increase). + +# Let's talk a bit more about the required pressure drop, seems important. +The required pressure drop required by cavitation could be provided by the propagation of ultrasonic acoustic waves and hydrodynamic pressure drops, such as constrictions or the rotational dynamics of turbomachinery. [cite:@GEVARI2020115065] + + +# Now do the materials point +A material exposed to such a myriad of micro-bombardment can be severly eroded, as the high stress levels exceed the resistance of the material, such as yield strength, ultimate strength or fatigue limit, leading to removal of material from the surface. + +# Let's talk a little more about sub-surface cracks +Bubble collapse can cause surface/sub-surface cracks, which are enhanced at stress risers (voids, defects, notches), leading to micro-cracks. The microcracks propagate + +# Witty remark to explain why cavitation erosion is cool? Meh? Remove if unncessary +The high value of the strain rate in cavitation erosion makes it rather comparable to explosions or projectile impacts, albeit with very limited volume of deformation and repeated impact loads. + + +#+BEGIN_COMMENT +Imagine we've got two main ways things change their phase: +boiling, which is like turning up the heat until water decides it's too hot and wants to become steam; +and cavitation, which is more like giving water so much room to breathe that it gets dizzy and starts forming bubbles. + +Now, whether we're heating things up or letting the pressure down, the secret that lets this change happen is when the pressure around our water whispers, "It's time," by hitting the saturated vapor pressure. +So, in a nutshell, it's all about hitting that sweet spot where the water feels just right to jump into its next costume, be it vapor or bubbles. + +To make cavitation happen — think of it as getting water to the point where it starts popping bubbles — you can use sound waves that travel through the fluid, making the pressure go down. + +Also, if you mess with the path the fluid takes, like squeezing it through tight spots or whirling it around in pumps and propellers, that can also drop the pressure just right. It's like setting up an obstacle course for the fluid; the hurdles and twists help create those bubble-making low-pressure zones. +#+END_COMMENT + +When a liquid is subject to ultrasound, tiny bubbles may occur and collapse. +High local pressure, temperature, and velocity fields are formed due to cavitation. + +In an ultrasonic cavitation field, the acoustic energy can be divided into two parts: +- acoustic propagation energy $E_{pa}$ + $E_{pa}$ is transmitted in the medium before dissipating into internal energy. +- cavitation energy $E_{ca}$ + The energy absorbed by cavitation bubbles is converted into mechanical energy $E_{me}$ + + +# The cavitation erosion phenomenon is the major problem confronting designers and users +of high-speed hydrodynamic system. It occurs mostly in fluid-flow machinery, for example +pumps, water turbines, marine propellers, also in devices in the chemical and petrochemical +industries, in diesel engines and pipelines [1-7]. Cavitation erosion is a reason of a drop of +efficiency, an increase of noise and a decrease of service life of the systems [2-4,6]. +Therefore, an interest of investigations of materials resistant to cavitation erosion remains at +high level from many years. + + + +* Synergy evaluation +Pure erosion (E): Two different methods were employed for the pure +erosion test. Three samples were subjected to erosion performed in 5 L of +triple distilled water for 1 h. And three samples were subjected to +cavitation erosion in 3.5% NaCl solution with cathodic protection for 1 h. +• Pure corrosion (C): Four samples were subjected to in-situ +electrochemical measurements kept at open circuit potential (OCP), and +electrochemical impedances spectroscopy (EIS) analysis were conducted +in 3.5% NaCl solution for 1 h. Two sample materials were also subjected +to potentiodynamic polarization, at a potential range between -1 V to 2 V, +to obtain C by applying Faradaic conversion. +284 +• Combined cavitation erosion-corrosion (T): all six samples were cavitated +in 5 L of 3.5% NaCl solution for 1 h while subjected to OCP. + + +* Experimental procedure + + +The masses of the samples are to be recorded before and after each experiment with a precision mass balance for gravimetric analyses. + + +The samples are to be left inside individual clean plastic bags for a week to ensure the formation of air-formed oxide films. + + + +The Q500 Sonicator has an operating frequency of 20 KHz and the output amplitude can be controlled by setting a range from 1 to 100% of the maximum vibration amplitude ASTM G32 55 um. + +The tip of the ultrasonic probe, made of niobium alloy +C103, is 12.7 mm in diameter. It is positioned in the center of +the beaker and the distance between the probe tip and the surface +of the water is about 2.0 cm. + + +The piezoelectric signal of the acoustic sensor is to be acquired by an oscilloscope. + + +* Experiment monitoring + + + + +* Working liquid properties + +Kind of liquid (water) applied, tap/distilled +Temperature, °C +pH indicator +contents of dissolved air +contents of undissolved air +other chemical additives + + + +* Research Qurstions + + +How do the HIP treated Stellite alloys compare with the untreated alloys in terms of: + - mechanical properties + - hardness + - tensile strength + - Resistance to Erosion-Corrosion + - Abrasive Wear resistance + - Adhesive Wear Resistance + - Erosion Wear Resistance + - Microstructure + - Grain size + - Phase distribution + - Porosity + - Homogeneity and Distribution of Elements in blends + - Performance in harsh environmental conditions + - High temperature + - Corrosive Environment + - Polarization Curves + Potentiodynamic polarization measurements in accordance with ASTM G5 and G59 in different electrolyte solutions to characterize performance of alloys in terms of open circuit potential, passivation behavior, and pitting potentials. + + A polarization curve is a plot of current density ($i$) versus electrode potential ($E$) for a specific electrode-electrolyte combination. Plots of $log |i|$ vs. $E$ or vs. $(E – Eo)$ are called polarization curves. The polarization curve is the basic kinetic law for any electrochemical reaction. + + + + - Cyclic Polarization +Cyclic potentiodynamic polarization technique is a relatively non-destructive measurement that can provide information about the corrosion rate, corrosion potential, susceptibility to pitting corrosion of the metal, and concentration limitation of the electrolyte in the system. The technique is built on the idea that prediction of the behavior of a metal in an environment can be made by forcing the material from its steady state condition and monitoring how it responds to the force as the force is removed at a constant rate and the system is reversed to its steady state condition. + + + + + +* COMMENT Learning Outcomes - Subject Mastery + +Understanding, Knowledge, and Cognitive Skills +For the core science/engineering area that is the subject of the project preparation work, the +student should demonstrate: +- A knowledge and an understanding of the subject's scope, terminology, and conventions +- A critical understanding of the subject's principal theories, principles, and concepts, and certain specialist topics within these +- An extensive, detailed, and critical knowledge and understanding that is informed by developments at the forefront of the subject +- A critical awareness of current issues in the subject +- Apply critical analysis, evaluation, and synthesis to issues that are at the forefront of informed by developments at the forefront of a subject/discipline. +- Identify, conceptualize, and define new and abstract problems and issues. +- Develop original and creative responses to problems and issues. +- Critically review, consolidate, and extend knowledge, skills practices, and thinking in a subject/discipline. +- Deal with complex issues and make judgments relevant to the design of research in the absence of complete or consistent data/information. + + +* COMMENT Scholarship, Enquiry, and Research (Research-Informed Learning) + +For the core science/engineering area that is the subject of the project preparation work, the +student should demonstrate the ability to: +- Apply a range of standard and specialized research inquiry techniques, evidenced by a detailed literature review of the relevant subject area +- Plan a significant project of research, investigation, or development, as evidenced in a written project proposal and plan +- The Module will use Microsoft’s MS Project to illustrate how software packages can be used to support the successful planning and management of projects. +- Demonstrate originality or creativity in interpreting prior work on the subject and applying this to the design of his / her research project + + + +Learning Outcomes - Personal Abilities +Industrial, Commercial & Professional Practice + +The student should, +- Deal with complex professional issues and make informed judgments on issues not addressed by current professionals and/or practices. +- Demonstrate an awareness of the application of his / her work in an industrial and/or commercial context + +Autonomy, Accountability & Working with Others + +The student should, +- Exercise substantial autonomy and initiative in planning and managing his / her research +- Take responsibility for his / her work and interaction with others +- Take responsibility for accessing and using a significant range of resources including literature, electronic documents, and software / computational resources. +- Demonstrate initiative by making an identifiable contribution to planning his / her research +- Exercise critical reflection on his/ her own and others' roles and responsibilities. Communication, Numeracy & ICT +The student should be able to use a range of advanced and specialized skills as appropriate to the subject of the project preparation work, including: +- Written communication in the form of a project proposal, literature review, and detailed project plan +- Dialogue with other students, researchers, and academic staff +- Making effective use of software to prepare written work and collect and/or manipulate data. +- Undertake critical evaluations of a wide range of written, numerical, and graphical information + + + + +* Flexing with the LitReview list + +%@ARTICLE{Lavigne2022, +%@ARTICLE{Hou2020, +%@ARTICLE{Liu2019, +%@ARTICLE{Zhang20191060, +%@ARTICLE{E2019246, +%@ARTICLE{Romero2019581, +%@ARTICLE{Romero2019518, +%@ARTICLE{Lei20119, +%@ARTICLE{Qin2011209, +%@ARTICLE{Ding200866, +%@ARTICLE{Feng2006558, + +#+BEGIN_SRC bibtex +@ARTICLE{Wang2023, +author={Wang, L. and Mao, J. and Xue, C. and Ge, H. and Dong, G. and Zhang, Q. and Yao, J.}, +title={Cavitation-Erosion behavior of laser cladded Low-Carbon Cobalt-Based alloys on 17-4PH stainless steel}, +journal={Optics and Laser Technology}, +year={2023}, +volume={158}, +doi={10.1016/j.optlastec.2022.108761}, +art_number={108761}, +note={cited By 5}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Szala2022741, +author={Szala, M. and Chocyk, D. and Turek, M.}, +title={Effect of Manganese Ion Implantation on Cavitation Erosion Resistance of HIPed Stellite 6}, +journal={Acta Physica Polonica A}, +year={2022}, +volume={142}, +number={6}, +pages={741-746}, +doi={10.12693/APhysPolA.142.741}, +note={cited By 0}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Lavigne2022, +author={Lavigne, O. and Cinca, N. and Ther, O. and Tarrés, E.}, +title={Effect of binder nature and content on the cavitation erosion resistance of cemented carbides}, +journal={International Journal of Refractory Metals and Hard Materials}, +year={2022}, +volume={109}, +doi={10.1016/j.ijrmhm.2022.105978}, +art_number={105978}, +note={cited By 3}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Mitelea2022967, +author={Mitelea, I. and Bordeaşu, I. and Mutaşcu, D. and Buzdugan, D. and Craciunescu, C.M.}, +title={Cavitation resistance of Stellite 21 coatings tungsten inert gas (TIG) deposited onto duplex stainless steel X2CrNiMoN22-5-3}, +journal={Materialpruefung/Materials Testing}, +year={2022}, +volume={64}, +number={7}, +pages={967-976}, +doi={10.1515/mt-2021-2169}, +note={cited By 1}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Liu2022, +author={Liu, J. and Chen, T. and Yuan, C. and Bai, X.}, +title={Effect of corrosion on cavitation erosion behavior of HVOF sprayed cobalt-based coatings}, +journal={Materials Research Express}, +year={2022}, +volume={9}, +number={6}, +doi={10.1088/2053-1591/ac78c9}, +art_number={066402}, +note={cited By 5}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Sun2021, +author={Sun, J. and Yan, Y. and Li, B. and Shi, Q. and Xu, T. and Zhang, Q. and Yao, J.}, +title={Comparative Study on Cavitation-Resistance and Mechanism of Stellite-6 Coatings Prepared with Supersonic Laser Deposition and Laser Cladding}, +journal={Zhongguo Jiguang/Chinese Journal of Lasers}, +year={2021}, +volume={48}, +number={10}, +doi={10.3788/CJL202148.1002118}, +art_number={1002118}, +note={cited By 6}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Szala2021, +author={Szala, M. and Chocyk, D. and Skic, A. and Kamiński, M. and Macek, W. and Turek, M.}, +title={Effect of nitrogen ion implantation on the cavitation erosion resistance and cobalt-based solid solution phase transformations of HIPed stellite 6}, +journal={Materials}, +year={2021}, +volume={14}, +number={9}, +doi={10.3390/ma14092324}, +art_number={2324}, +note={cited By 22}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Zhang2021, +author={Zhang, Q. and Wu, L. and Zou, H. and Li, B. and Zhang, G. and Sun, J. and Wang, J. and Yao, J.}, +title={Correlation between microstructural characteristics and cavitation resistance of Stellite-6 coatings on 17-4 PH stainless steel prepared with supersonic laser deposition and laser cladding}, +journal={Journal of Alloys and Compounds}, +year={2021}, +volume={860}, +doi={10.1016/j.jallcom.2020.158417}, +art_number={158417}, +note={cited By 20}, +document_type={Article}, +source={Scopus}, +} + +@CONFERENCE{Cinca202115, +author={Cinca, N. and Lavigne, O. and Ther, O. and Tarrés, E.}, +title={Cavitation erosion characterization of cemented carbides}, +journal={Advances in Tungsten, Refractory and Hardmaterials�2021 - Proceedings of the 10th International Conference on Tungsten, Refractory and Hardmaterials}, +year={2021}, +pages={15-31}, +note={cited By 0}, +document_type={Conference Paper}, +source={Scopus}, +} + +@ARTICLE{Hou2020, +author={Hou, G. and Ren, Y. and Zhang, X. and Dong, F. and An, Y. and Zhao, X. and Zhou, H. and Chen, J.}, +title={Cavitation erosion mechanisms in Co-based coatings exposed to seawater}, +journal={Ultrasonics Sonochemistry}, +year={2020}, +volume={60}, +doi={10.1016/j.ultsonch.2019.104799}, +art_number={104799}, +note={cited By 31}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Liu2019, +author={Liu, J. and Bai, X. and Chen, T. and Yuan, C.}, +title={Effects of cobalt content on the microstructure, mechanical properties and cavitation erosion resistance of HVOF sprayed coatings}, +journal={Coatings}, +year={2019}, +volume={9}, +number={9}, +doi={10.3390/coatings9090534}, +art_number={534}, +note={cited By 29}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Zhang20191060, +author={Zhang, H. and Gong, Y. and Chen, X. and McDonald, A. and Li, H.}, +title={A Comparative Study of Cavitation Erosion Resistance of Several HVOF-Sprayed Coatings in Deionized Water and Artificial Seawater}, +journal={Journal of Thermal Spray Technology}, +year={2019}, +volume={28}, +number={5}, +pages={1060-1071}, +doi={10.1007/s11666-019-00869-x}, +note={cited By 29}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{E2019246, +author={E, M. and Hu, H.X. and Guo, X.M. and Zheng, Y.G.}, +title={Comparison of the cavitation erosion and slurry erosion behavior of cobalt-based and nickel-based coatings}, +journal={Wear}, +year={2019}, +volume={428-429}, +pages={246-257}, +doi={10.1016/j.wear.2019.03.022}, +note={cited By 49}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Romero2019581, +author={Romero, M.C. and Tschiptschin, A.P. and Scandian, C.}, +title={Low temperature plasma nitriding of a Co30Cr19Fe alloy for improving cavitation erosion resistance}, +journal={Wear}, +year={2019}, +volume={426-427}, +pages={581-588}, +doi={10.1016/j.wear.2019.01.019}, +note={cited By 10}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Romero2019518, +author={Romero, M.C. and Tschiptschin, A.P. and Scandian, C.}, +title={Cavitation erosion resistance of a non-standard cast cobalt alloy: Influence of solubilizing and cold working treatments}, +journal={Wear}, +year={2019}, +volume={426-427}, +pages={518-526}, +doi={10.1016/j.wear.2018.12.044}, +note={cited By 13}, +document_type={Article}, +source={Scopus}, +} + +@CONFERENCE{Mutascu2019776, +author={Mutaşcu, D. and Mitelea, I. and Bordeaşu, I. and Buzdugan, D. and Franţ, F.}, +title={Cavitation resistant layers from stellite alloy deposited by TIG welding on duplex stainless steel}, +journal={METAL 2019 - 28th International Conference on Metallurgy and Materials, Conference Proceedings}, +year={2019}, +pages={776-780}, +note={cited By 1}, +document_type={Conference Paper}, +source={Scopus}, +} + +@ARTICLE{Kovalenko2019175, +author={Kovalenko, V.I. and Klimenko, A.A. and Martynenko, L.I. and Marinin, V.G.}, +title={Erosion of co-cr-w alloy and coatings on its basis under cavitation in and}, +journal={Problems of Atomic Science and Technology}, +year={2019}, +volume={2019}, +number={5}, +pages={175-178}, +note={cited By 0}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{E201890, +author={E, M. and Hu, H.-X. and Guo, X.-M. and Zheng, Y.-G. and Bai, L.-L.}, +title={Microstructure and cavitation erosion resistance of cobalt-based and nickel-based coatings}, +journal={Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment}, +year={2018}, +volume={39}, +number={1}, +pages={90-96}, +doi={10.13289/j.issn.1009-6264.2017-0357}, +note={cited By 7}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Ding201797, +author={Ding, Y. and Liu, R. and Yao, J. and Zhang, Q. and Wang, L.}, +title={Stellite alloy mixture hardfacing via laser cladding for control valve seat sealing surfaces}, +journal={Surface and Coatings Technology}, +year={2017}, +volume={329}, +pages={97-108}, +doi={10.1016/j.surfcoat.2017.09.018}, +note={cited By 58}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Guo2016123, +author={Guo, S. and Zhou, G. and Guo, X. and Yi, Y. and Yao, J.}, +title={Influence of scanning velocity on microstructure and properties of Co-based alloy coatings by diode laser cladding}, +journal={Jinshu Rechuli/Heat Treatment of Metals}, +year={2016}, +volume={41}, +number={8}, +pages={123-127}, +doi={10.13251/j.issn.0254-6051.2016.08.028}, +note={cited By 2}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Ciubotariu201698, +author={Ciubotariu, C.-R. and Frunzəverde, D. and Mərginean, G. and Serban, V.-A. and Bîrdeanu, A.-V.}, +title={Optimization of the laser remelting process for HVOF-sprayed Stellite 6 wear resistant coatings}, +journal={Optics and Laser Technology}, +year={2016}, +volume={77}, +pages={98-103}, +doi={10.1016/j.optlastec.2015.09.005}, +note={cited By 44}, +document_type={Review}, +source={Scopus}, +} + +@ARTICLE{Ciubotariu2016154, +author={Ciubotariu, C.-R. and Secosan, E. and Marginean, G. and Frunzaverde, D. and Campian, V.C.}, +title={Experimental study regarding the cavitation and corrosion resistance of stellite 6 and self-fluxing remelted coatings}, +journal={Strojniski Vestnik/Journal of Mechanical Engineering}, +year={2016}, +volume={62}, +number={3}, +pages={154-162}, +doi={10.5545/sv-jme.2015.2663}, +note={cited By 12}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Singh201487, +author={Singh, R. and Kumar, D. and Mishra, S.K. and Tiwari, S.K.}, +title={Laser cladding of Stellite 6 on stainless steel to enhance solid particle erosion and cavitation resistance}, +journal={Surface and Coatings Technology}, +year={2014}, +volume={251}, +pages={87-97}, +doi={10.1016/j.surfcoat.2014.04.008}, +note={cited By 120}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Hattor2014257, +author={Hattor, S.}, +title={Recent investigations on cavitation erosion at the university of fukui}, +journal={Fluid Mechanics and its Applications}, +year={2014}, +volume={106}, +pages={257-282}, +doi={10.1007/978-94-017-8539-6_11}, +note={cited By 2}, +document_type={Article}, +source={Scopus}, +} + +@CONFERENCE{Depczynski20131045, +author={Depczynski, W. and Radek, N.}, +title={Properties of elektro sparc deposited stellite coating on mild steel}, +journal={METAL 2013 - 22nd International Conference on Metallurgy and Materials, Conference Proceedings}, +year={2013}, +pages={1045-1050}, +note={cited By 3}, +document_type={Conference Paper}, +source={Scopus}, +} + +@ARTICLE{Singh2012498, +author={Singh, R. and Tiwari, S.K. and Mishra, S.K.}, +title={Cladding of tungsten carbide and stellite using high power diode laser to improve the surface properties of stainless steel}, +journal={Advanced Materials Research}, +year={2012}, +volume={585}, +pages={498-501}, +doi={10.4028/www.scientific.net/AMR.585.498}, +note={cited By 2}, +document_type={Conference Paper}, +source={Scopus}, +} + +@ARTICLE{Romo201216, +author={Romo, S.A. and Santa, J.F. and Giraldo, J.E. and Toro, A.}, +title={Cavitation and high-velocity slurry erosion resistance of welded Stellite 6 alloy}, +journal={Tribology International}, +year={2012}, +volume={47}, +pages={16-24}, +doi={10.1016/j.triboint.2011.10.003}, +note={cited By 68}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Lei20119, +author={Lei, Y. and Li, T. and Qin, M. and Chen, X. and Ye, Y.}, +title={Cavitation erosion resistance of Co alloy coating on 304 stainless steel by TIG cladding}, +journal={Hanjie Xuebao/Transactions of the China Welding Institution}, +year={2011}, +volume={32}, +number={7}, +pages={9-12}, +note={cited By 4}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Qin2011209, +author={Qin, C.-P. and Zheng, Y.-G.}, +title={Cavitation erosion behavior of a laser clad Co-based alloy on 17-4PH stainless steel}, +journal={Corrosion Science and Protection Technology}, +year={2011}, +volume={23}, +number={3}, +pages={209-213}, +note={cited By 8}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Hattori20091954, +author={Hattori, S. and Mikami, N.}, +title={Cavitation erosion resistance of stellite alloy weld overlays}, +journal={Wear}, +year={2009}, +volume={267}, +number={11}, +pages={1954-1960}, +doi={10.1016/j.wear.2009.05.007}, +note={cited By 68}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Ding200866, +author={Ding, Z.-X. and Wang, Q. and Chen, Z.-H. and Zhang, S.-Y. and Zhao, G.}, +title={Research on cavitation erosion resistance of spraying and fusing co-based and Ni-based coatings}, +journal={Hunan Daxue Xuebao/Journal of Hunan University Natural Sciences}, +year={2008}, +volume={35}, +number={1}, +pages={66-70}, +note={cited By 0}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Feng2006558, +author={Feng, L.-H. and Lei, Y.-C. and Zhao, X.-J.}, +title={Cavitation behavior of a Co-base alloy}, +journal={Corrosion and Protection}, +year={2006}, +volume={27}, +number={11}, +pages={558-560}, +note={cited By 0}, +document_type={Article}, +source={Scopus}, +} + +@ARTICLE{Garzon2005145, +author={Garzón, C.M. and Thomas, H. and Dos Santos, J.F. and Tschiptschin, A.P.}, +title={Cavitation erosion resistance of a high temperature gas nitrided duplex stainless steel in substitute ocean water}, +journal={Wear}, +year={2005}, +volume={259}, +number={1-6}, +pages={145-153}, +doi={10.1016/j.wear.2005.02.005}, +note={cited By 33}, +document_type={Conference Paper}, +source={Scopus}, +} +#+END_SRC + +* Timetable + +** DONE Week 1 +CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-15 Mon> +Introduction to the course +Assessment briefing +Canvas, Turnitin +Citing, Referencing, Plagiarism + +** DONE Week 2 +CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-22 Mon> +Time Management +Why critical analysis + +** DONE Week 3 +CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-01-29 Mon> +Taking Ownership of Critical thinking in an academic context +What is critical writing? +The “Park” Group exercise + +** DONE Week 4 +CLOSED: [2024-02-26 Mon 19:05] SCHEDULED: <2024-02-05 Mon> + +The “Park” solution – Class discussion +Literature Searching & the Literature Review +The Philosophy and nature of research + +** DONE Week 5 +CLOSED: [2024-02-26 Mon 19:06] SCHEDULED: <2024-02-12 Mon> + +Creating an annotated bibliography to support writing a literature review +Annotated bibliography -– Class discussion + +** DONE Week 7 +CLOSED: [2024-02-26 Mon 19:06] SCHEDULED: <2024-02-26 Mon> + +Data analysis and presentation + +** DONE Week 8 +CLOSED: [2024-03-19 Tue 16:45] SCHEDULED: <2024-03-04 Mon> + +Risk, Health & Safety +Research Methods – Course Portfolio: Background research + +** DONE Week 9 +CLOSED: [2024-03-19 Tue 16:45] SCHEDULED: <2024-03-11 Mon> + +Research Project Management: Planning & Gantt Charts: MS Project Application (Part 1) +Research Project Management: Planning & Gantt Charts: MS Project Application (Part 2) + +* Project Proposal + + +Grade contribution - 30% total weighting +Word count - approx. 1,000 words which include the word count for the work plan + +- [ ] Work Packages + Was a WBS (activities and steps) defined? +- [ ] Resources + Were the resources needed for the project well-defined? + - Were they in place already? + - Was there a statement of the planning needed to put the necessary resources in place? +- [ ] Associated risks + - Were the risks which might affect the success of the project defined? + - Were measures suggested to mitigate these? + + +** Overview +# This part of the proposal is like an "executive summary" or abstract of what the document contains. +# It should be no more than a single page or even less, double-spaced. +# Essentially it is a "map" that shows the territory through which the reader will be led. +# This section should be written last (as summary) after all other sections have been prepared. + +- [ ] Context & Novelty + - How well was the project placed in the context of previous work? + - How well was the novelty of the project expressed? + +** Background +# BACKGROUND AND GENERAL GOALS OF THE THESIS: +# The major body of the document begins with any background that needs to be understood and helps in understanding what is to be done and why. +# It also explains in general narrative terms the main question or questions that will be addressed and describes broadly the research strategy that will be used to bring together the information needed to answer those questions. + +*** Statement of objectives. +# Clearly and concisely, what are the general goals of the thesis. Each thesis may have distinct goals. +# Is your thesis project purely descriptive of a new phenomena? +# Is it empirically testing causal relationships between particular variables of interest? +# Are your providing a critical evaluation of a particular topic or framework? +# Are you providing a new perspective by presenting a new typology? +# Are you creating, implementing, or testing a new research tool? +# Any such missions of the thesis should be clearly stated in this section. + +- [ ] Objectives + - [ ] Were the aims of the project clearly expressed? + Were they specific and measurable? Were they realistic? Were adequate timescales referred to? + - [ ] What is going to be investigated? + - [ ] What is going to be measured? + +*** Significance of the project +# What is the social importance of this thesis. +# That is, how will this thesis aid our collective understanding of emerging media, in terms of theory and real-world application to a particular social domain (e.g., politics, health, entertainment, design). + +- [ ] Expected outcomes + - Was the anticipated result of the project clearly defined? + - Were sensible interim milestones identified? +- [ ] Beneficiaries + - Is it made clear who would benefit from the work carried out in the project? + +** Literature Review +# This section is an initial (not the final) report of what others who have studied the same problem or topic have found or concluded. This review should be selective, and should be limited to information that is relevant to the thesis topic. This section should include formal statement of research questions and/or hypotheses derived from your review of the extant literature. A fuller review should come later as part of the thesis itself, including extensive consideration of prior studies or other writings that focus directly on the issue under investigation in order to show the state of knowledge that already exists. + +- [ ] Context + Has sufficient evidence been presented of the previous work on the subject? +- [ ] Significance + Is the significance of the previous work clearly stated and critically evaluated in terms of its contribution to the subject and its wider impact? +- [ ] Relevance + Are the cited sources and the discussion relating to these relevant to the project? +- [ ] Methodologies + Have sufficient methodologies been explored in the review to place the proposed methodology in its context? +- [ ] Logical progression and argument + Does the review clearly explain and justify the stated aims and objectives and the chosen methodology? +- [ ] Structure of the report + Is the report's structure adequate to usefully convey the important information? +- [ ] Presentation Quality + Does the report meet publication standards in terms of English usage, use of tables and figures to underpin the argument in the text, and general level of presentation and layout? +- [ ] Referencing and bibliography + Are sources adequately and properly referenced in the text and figure/table captions? Is the bibliography adequately formatted following a generally recognized referencing convention? +- [ ] Length + Is the length of the review within the range and appropriate to the material presented (not too many irrelevant words but enough relevant words)? +- [ ] Originality + Is the content of the report the work of the student? + Has the student avoided copying blocks of text or figures verbatim from other sources? + (Marks should be deducted for excessive use of others' published work, even if the use is attributed.) +** Proposed method +# This section should provide a clear description of the methods you will implement for conducting your thesis project. In order to gather information, will you conduct an experiment, a survey, a content analysis, a focus group, or some other means of data collection? This section should specifically describe the following, as applicable to your intended method of inquiry: + +*** Procedure +# What will be the general steps for completing data collection? Here you should describe any all general steps for recruiting participants, conducting an experiment, leading a focus group, distributing surveys, gathering publicly-available data, or otherwise completing your intended means of data collection. + +*** Measures +# If examining the associative or causal relationships between variables, how exactly will you measure or operationalize these variables. + +** Overall structure of the proposed thesis +# In this section you should provide a brief outline of the general structure of your intended thesis. If a typical empirical investigation, this may simply include an introduction, literature review, methods section, results section, and closing discussion. If another format or type of thesis, similarly provide a general outline of the overall structure of the future deliverable. + + +- Abstract + Succinct abstract of less than one page. +- Table of content + The table of content lists all chapters (headings/subheadings) including page number. +- Introduction + Explain why this work is important giving a general introduction to the subject, list the basic knowledge needed and outline the purpose of the report. +- Background and results to date + List relevant work by others, or preliminary results you have achieved with a detailed and accurate explanation and interpretation. Include relevant photographs, figures or tables to illustrate the text. This section should frame the research questions that your subsequent research will address. +- Goal + List the main research question(s) you want to answer. Explain whether your research will provide a definitive answer or simply contribute towards an answer. +- Methodology + Explain the methods and techniques which will be used for your project depending on the subject: field work, laboratory work, modeling technique, interdisciplinary collaboration, data type, data acquisition, infrastructure, software, etc. +- Time Plan 3 for Master’s Project Proposal and Master’s Thesis + Give a detailed time plan. Show what work needs to be done and when it will be completed. Include other responsibilities or obligations. +- Discussion / Conclusion + Explain what is striking/noteworthy about the results. Summarize the state of knowledge and understanding after the completion of your work. Discuss the results and interpretation in light of the validity and accuracy of the data, methods and theories as well as any connections to other people’s work. Explain where your research methodology could fail and what a negative result implies for your research question. +- Acknowledgements + Thank the people who have helped to successfully complete your project, like project partners, tutors, etc. +- Reference & Literature (Bibliography) + List papers and publication you have already cited in your proposal or which you have collected for further reading. The style of each reference follows that of international scientific journals. +- Appendix + Add pictures, tables or other elements which are relevant, but that might distract from the main flow of the proposal. + +** Project Management + +# The students must use Microsoft’s MS Project or a similar application to illustrate how software packages can be used to support the successful planning and management of projects. MS Project Guidelines, Material, and Computer Lab exercises can be accessed on Canvas. +# This is a one-page diagrammatic work plan following the appropriate format of a “Microsoft Office Project Gantt chart view and supplement information in the text (” to present and include: + +- [ ] Title & Headline Info + - [ ] Project Name + - [ ] Anticipated start /finish dates and durations +- [ ] Work-Packages + Are work packages clearly expressed? + Do the work packages in the work plan match those in the project proposal? +- [ ] Timescale + Are the work packages in the right chronological order? + Has sufficient time been allocated to each work package? + - [ ] Activities for Course B81EZ background Research + from January to the end of March + - [ ] Activities for B51MD dissertation execution work + from May to the end of August + - [ ] Realistic break in activities + A break for the Easter holidays and second-semester exams + - [ ] Full push during summer + Full project activities during the summer and final dissertation submission +- [ ] Task Dependencies + Is it clear which work packages must be completed before others can begin? + Have all the necessary dependencies been considered? + Are these effectively illustrated by the plan? +- [ ] Project Milestones and Deliverables + - [ ] Are milestones and deliverables clearly expressed? + - [ ] Do they match those in the project proposal? + - [ ] Are they indicated in a sensible chronological order? +- [ ] Health and Safety / Ethical aspects + - [ ] Were the Health and Safety risks addressed? + - [ ] Were measures suggested to mitigate these? + - [ ] Were ethical considerations addressed if appropriate? + +*** Health and Safety aspects + +Research may generate risks during the exploration of new ideas and processes, especially if changes occur without a review of possible risks. This section is aimed at minimising the risks to the health and safety of the author and other University researchers when engaged in research activities in University premises. + +**** Lone working guidance + +For the purposes of this MSc thesis, lone working is defined as someone who works on their own with no close or direct supervision, especially if they do not have visual or audible communication with someone who can summon assistance in the event of an accident or illness. + +Risk assessments need to be collaboratively discussed with supervisor for: +- low-risk environment such as lone working at an office desk +- high-risk environment such as operating equipment + +Risk assessments need to be communicated to the lab manager for feedback. + +- [ ] Appropriate working environmment + HVAC & Ventilation + Lighting + Harmful chemicals? +- [ ] Welfare facilities and Medical concerns + Are the welfare facilities adequate and accessible? + Are first-aid facilities available? + Is the student medically fit to undertake the work alone? + Is there a requirement for on-going health checks, health monitoring? +- [ ] Contingency plans + Are there contingency plans in place should an alert/alarm be raised by a lone worker and are these plans well known and rehearsed: + - what to do + - who to contact, etc? + - means of communication? mobile phone, Safezone app + +**** Control measures + +- [ ] Elimination or substitution + Can less hazardous materials, equipment or processes be used? +- [ ] Engineering controls + Can risks be mitigated at source using engineering controls such as equipment guards and interlocks? +- [ ] Administrative controls + Can suitable systems of work be designed, specifying what is required in terms of training, rules, procedures and supervision. +- [ ] Personal Protective Clothing and Equipment + What individual protective measures are required, such as personal protective equipment or health surveillance/ + + + +* Standards - ASTM & ISO + +** ISO 4499 - Metallographic determination of microstructure + +ISO 4499-1:2020 +Hardmetals — Metallographic determination of microstructure — Part 1: Photomicrographs and description +ISO 4499-2:2020 +Hardmetals — Metallographic determination of microstructure — Part 2: Measurement of WC grain size + +ISO 4499-3:2016 +Hardmetals — Metallographic determination of microstructure — Part 3: Measurement of microstructural features in Ti (C, N) and WC/cubic carbide based hardmetals + +ISO 4499-4:2016 +Hardmetals — Metallographic determination of microstructure — Part 4: Characterisation of porosity, carbon defects and eta-phase content + + +** Vickers + +id:Sangwal2003511 does great work in explaining the empirical relationships of Vickers hardness on cobalt-based alloys between different stuff. You know how to make this even cooler. Make a paper! + +Would be even cooler if you did one with image measurement of Vickers + + +** NoAuthor2005 - Metallic Materials - Vickers Hardness Test - Part 1: Test Method +:PROPERTIES: +:ID: NoAuthor2005 +:END: + +#+BEGIN_SRC bibtex +@ARTICLE{NoAuthor2005, +title={Metallic Materials - Vickers Hardness Test - Part 1: Test Method}, +journal={Metallic Materials - Vickers Hardness Test - Part 1: Test Method}, +year={2005}, +note={cited By 580}, +} +#+END_SRC + +** NoAuthor2009 - Method of Test at Ambient Temperature +:PROPERTIES: +:ID: NoAuthor2009 +:END: + +#+BEGIN_SRC bibtex +@ARTICLE{NoAuthor2009, +title={Method of Test at Ambient Temperature}, +journal={Method of Test at Ambient Temperature}, +year={2009}, +note={cited By 5}, +} +#+END_SRC + +** NoAuthor0000 - ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus +:PROPERTIES: +:ID: NoAuthor0000 +:END: + +#+BEGIN_SRC bibtex +@ARTICLE{NoAuthor0000, +journal={ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus}, +year={0000}, +note={cited By 3}, +} +#+END_SRC + + + + + + +** NoAuthor2010 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus +:PROPERTIES: +:ID: NoAuthor2010 +:END: + +#+BEGIN_SRC bibtex +@ARTICLE{NoAuthor2010, +title={Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus}, +journal={Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus}, +year={2010}, +note={cited By 243}, +} +#+END_SRC + +** NoAuthor2016 - Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear +:PROPERTIES: +:ID: NoAuthor2016 +:END: + +#+BEGIN_SRC bibtex +@ARTICLE{NoAuthor2016, +title={Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear}, +journal={Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear}, +year={2016}, +note={cited By 282}, +} +#+END_SRC + + + +* Phase + +Co3W +Co3W3C +Co6W3C +Co + + +Co-W (Cobalt-Tungsten) + + +Blend A +- α-cobalt (FCC) +- Cr7C3 +- Cr23C6 +- Co7W6 +- Co6W6C +- Co3W + +Blend B +- α-cobalt (FCC) +- Cr7C3 +- Cr23C6 +- Co7W6 +- Co6W6C +- Co3W3C +- Co3W + +Blend C +- α-cobalt (FCC) +- Cr7C3 +- Cr23C6 +- Co7W6 +- Co6W6C +- Co3W + + +α-cobalt (FCC) +Cr7C3 +Cr23C6 +Co7W6 +Co6W6C +Co3W3C +Co3W + +id:Gui20171271 +| | Cr | Mo | Co | +| $M_{7}C_{3}$ | | | | +| $MC$ | | | | +| $M_{23}C_{3}$ | | | | +| $M_{6}C_{3}$ | | | | + + + + +* Effects of Indentation Loading Force and Number of Indentations on the MicroHardness Variation for Stellite +* Simulations + +https://github.com/stromatolith/RP_Bubble?tab=readme-ov-file + diff --git a/touchme b/touchme new file mode 100644 index 0000000..e69de29