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Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys / MEIHUI CHONG

Swansea University Author: MEIHUI CHONG

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DOI (Published version): 10.23889/SUThesis.71056

Abstract

This study explores the creep behaviour of three polycrystalline alloys—stainless steel 316, Haynes 282, and Inconel 713C—chosen for their varying precipitate volume fractions. The primary aim is to provide a comprehensive understanding of the underlying mechanisms that control creep behaviour in th...

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Published: Swansea 2025
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Whittaker, M., and Davies, H.
URI: https://cronfa.swan.ac.uk/Record/cronfa71056
first_indexed 2025-12-03T10:36:13Z
last_indexed 2025-12-05T09:33:37Z
id cronfa71056
recordtype RisThesis
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spelling 2025-12-03T10:39:23.1451967 v2 71056 2025-12-03 Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys aa977af099442d5ea681d7498c6c8f06 MEIHUI CHONG MEIHUI CHONG true false 2025-12-03 ONDF This study explores the creep behaviour of three polycrystalline alloys—stainless steel 316, Haynes 282, and Inconel 713C—chosen for their varying precipitate volume fractions. The primary aim is to provide a comprehensive understanding of the underlying mechanisms that control creep behaviour in these alloys, with a particular focus on determining the creep activation energies (Qc*) involved.SS316 displays a gradual transition in Qc* values (153–298 kJ/mol; up to 305 kJ/mol for plates), attributed to dislocation movement at low temperatures and twinning above yield stress at elevated conditions. Haynes 282 shows a wider range (276–427 kJ/mol),with γ′ precipitate resistance at low stress and forest hardening above yield strength.In contrast, Inconel 713C with highest volume fraction of precipitates, exhibits a constant Qc*, indicating creep governed by confined dislocation motion within γchannels, with no clear transition.To further examine deformation behaviour in SS316, cyclic creep tests were conducted between 600 °C/334 MPa and 700 °C/165 MPa. The results indicate that cyclic creep reduces the material’s service life and that the transition from dislocation cell formation to twin boundary formation contributes to an increased creep rate as the temperature rises from 600 °C to 700 °C. Additionally, when cycling from 700 °C to 600 °C, the creep rate was found to be higher than expected. This may be attributed to the retrograde formation of dislocations during the recovery phase, which are rapidly disrupted upon reloading.The findings reinforce the utility of the Wilshire equations in rationalising Qc* values and linking them to microstructural mechanisms. This provides a robust framework for predicting creep behaviour, aiding alloy development and high-temperature material optimisation. E-Thesis Swansea Creep, Wilshire equations, Activation energy, Stainless steel 316, Haynes 282, Inconel 713C 7 10 2025 2025-10-07 10.23889/SUThesis.71056 COLLEGE NANME Other/Subsidiary Companies - Not Defined COLLEGE CODE ONDF Swansea University Whittaker, M., and Davies, H. Doctoral Ph.D 2025-12-03T10:39:23.1451967 2025-12-03T10:32:52.6708543 Faculty of Science and Engineering School of Engineering and Applied Sciences - Materials Science and Engineering MEIHUI CHONG 1 71056__35731__90b7ac8bd4624801924ccdede03c481c.pdf 2025_Chong_M.final.71056.pdf 2025-12-03T10:35:43.3425451 Output 11186979 application/pdf E-Thesis – open access true Copyright: The author, Meihui Chong, 2025 Distributed under the terms of a Creative Commons Attribution 4.0 License (CC BY 4.0) true eng https://creativecommons.org/licenses/by/4.0/
title Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
spellingShingle Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
MEIHUI CHONG
title_short Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
title_full Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
title_fullStr Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
title_full_unstemmed Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
title_sort Understanding Creep Deformation and Lifing Approaches for Advanced Nickel and Steel Alloys
author_id_str_mv aa977af099442d5ea681d7498c6c8f06
author_id_fullname_str_mv aa977af099442d5ea681d7498c6c8f06_***_MEIHUI CHONG
author MEIHUI CHONG
author2 MEIHUI CHONG
format E-Thesis
publishDate 2025
institution Swansea University
doi_str_mv 10.23889/SUThesis.71056
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Materials Science and Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Materials Science and Engineering
document_store_str 1
active_str 0
description This study explores the creep behaviour of three polycrystalline alloys—stainless steel 316, Haynes 282, and Inconel 713C—chosen for their varying precipitate volume fractions. The primary aim is to provide a comprehensive understanding of the underlying mechanisms that control creep behaviour in these alloys, with a particular focus on determining the creep activation energies (Qc*) involved.SS316 displays a gradual transition in Qc* values (153–298 kJ/mol; up to 305 kJ/mol for plates), attributed to dislocation movement at low temperatures and twinning above yield stress at elevated conditions. Haynes 282 shows a wider range (276–427 kJ/mol),with γ′ precipitate resistance at low stress and forest hardening above yield strength.In contrast, Inconel 713C with highest volume fraction of precipitates, exhibits a constant Qc*, indicating creep governed by confined dislocation motion within γchannels, with no clear transition.To further examine deformation behaviour in SS316, cyclic creep tests were conducted between 600 °C/334 MPa and 700 °C/165 MPa. The results indicate that cyclic creep reduces the material’s service life and that the transition from dislocation cell formation to twin boundary formation contributes to an increased creep rate as the temperature rises from 600 °C to 700 °C. Additionally, when cycling from 700 °C to 600 °C, the creep rate was found to be higher than expected. This may be attributed to the retrograde formation of dislocations during the recovery phase, which are rapidly disrupted upon reloading.The findings reinforce the utility of the Wilshire equations in rationalising Qc* values and linking them to microstructural mechanisms. This provides a robust framework for predicting creep behaviour, aiding alloy development and high-temperature material optimisation.
published_date 2025-10-07T05:27:25Z
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score 11.089572

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