thesis/thesis_original.org

Cavitation Erosion in Blended Stellite Alloys

• Grain size
• Strain Energy
• Timeline latex
• Find out the SEM guy at BITS Pilani
• TODO
• Project Proposal
  • Abstract
  • Introduction
  • Aims and Objectives
  • Methodology
    • Work Packages
    • Resources
    • Associated risks
      • Technical Risks
      • Data Acquisition and Analysis
        • Pre-Experiment Preparation:
        • Quality Control Measures:
        • Data Management Protocols:
        • Real-Time Monitoring:
        • Data Validation and Verification:
        • Statistical Analysis Techniques:
        • Error Propagation Analysis:
        • Peer Review and Collaboration:
        • Documentation and Reproducibility:
  • Other stuff
    • Expected outcomes
    • Resources needed
    • Risks anticipated
    • Beneficiaries of work
• Literature review
• Introduction to Cavitation Erosion
• Cavitation Description
• Synergy evaluation
• Experimental procedure
• Experiment monitoring
• Working liquid properties
• Research Qurstions
• COMMENT Learning Outcomes - Subject Mastery
• COMMENT Scholarship, Enquiry, and Research (Research-Informed Learning)
• Flexing with the LitReview list
• Timetable
  • Week 1
  • Week 2
  • Week 3
  • Week 4
  • Week 5
  • Week 7
  • Week 8
  • Week 9
• Project Proposal
  • Overview
  • Background
    • Statement of objectives.
    • Significance of the project
  • Literature Review
  • Proposed method
    • Procedure
    • Measures
  • Overall structure of the proposed thesis
  • Project Management
    • Health and Safety aspects
      • Lone working guidance
      • Control measures
• Standards - ASTM & ISO
  • ISO 4499 - Metallographic determination of microstructure
  • Vickers
  • NoAuthor2005 - Metallic Materials - Vickers Hardness Test - Part 1: Test Method
  • NoAuthor2009 - Method of Test at Ambient Temperature
  • NoAuthor0000 - ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus
  • NoAuthor2010 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus
  • NoAuthor2016 - Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear
• Phase
• Effects of Indentation Loading Force and Number of Indentations on the MicroHardness Variation for Stellite
• Simulations

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}.

<SHOW GRAPH OF HARDNESS VS CAVITATION EROSION OF ALL YOUR REVIEW HERE. SHOW INCREASING HARDNESS INSIDE MATERIAL GROUPS>

<Strain energy being a good indicator and why Thiruvengadum's erosion strength is cool>. 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

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 ∝ \frac{1}{SE}

CavitationErosionBehaviourSteelPlateScroll

Timeline latex

Use for cavitation curves models

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.

Experiments are to be conducted using an ultrasonic vibratory horn, with fixed frequency 20 kHz and variable peak to peak amplitude.

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

Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics \cite{Franc2004265}.

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}.

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}.

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}.

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.

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}.

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}

To date, academic research pertaining to cavitation erosion specifically on HIP'd stellite alloys appears to be absent from the existing literature.

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.

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.

Aims and Objectives

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

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

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

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

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}.

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.

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.

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}.

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}.

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.

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.

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.

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.

Parameter	Value
Frequency	20 kHz
Peak-to-peak amplitude	50 um
Gap	0.5 mm
Horn diameter	15.9 mm

Parameters defined by ASTM G32

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}.

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},

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.

In seawater (and other corrosive media), the coupling of corrosion and cavitation erosion can cause significant material damage with complex, synergistic mechanisms

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

Cavitation erosion is a complex phenomenon that results from hydrodynamic elements and material characteristics. [cite:@Franc2004265]

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.

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.

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.

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.

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.

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.

As indicator for grid sensitivity study, we choose the vapor volume fraction integrated over the computational domain, as it describes the cavitating flow.

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

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.

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].

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).

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]

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.

Bubble collapse can cause surface/sub-surface cracks, which are enhanced at stress risers (voids, defects, notches), leading to micro-cracks. The microcracks propagate

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.

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.

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 $E_{me}$

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,

@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<6C>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},
}

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

• Context & Novelty

  • How well was the project placed in the context of previous work?
  • How well was the novelty of the project expressed?

Background

Statement of objectives.

• 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

• 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

• 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

Procedure

Measures

Overall structure of the proposed thesis

• 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

• 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

@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},
}

NoAuthor2009 - Method of Test at Ambient Temperature

@ARTICLE{NoAuthor2009,
title={Method of Test at Ambient Temperature},
journal={Method of Test at Ambient Temperature},
year={2009},
note={cited By 5},
}

NoAuthor0000 - ASTM G65-00: Standard Test Method for Measuring Abrasion Using the Dry Sand/rubber Wheel Apparatus

@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},
}

NoAuthor2010 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus

@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},
}

NoAuthor2016 - Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear

@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},
}

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