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Thermo-mechanical fatigue crack growth behaviour of Ti-6246 / JENNIE PALMER

Swansea University Author: JENNIE PALMER

  • Redacted version - open access under embargo until: 16th December 2025

DOI (Published version): 10.23889/SUthesis.58780

Abstract

Within the gas turbine engine, the high transient thermal stresses developed due to variations in power requirements during a typical flight cycle give rise to the phenomenon of thermo-mechanical fatigue (TMF). Associated with higher operating temperatures, the study of TMF within the gas turbine en...

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Published: Swansea 2021
Institution: Swansea University
Degree level: Doctoral
Degree name: EngD
Supervisor: Whittaker, Mark ; Williams, Steve
URI: https://cronfa.swan.ac.uk/Record/cronfa58780
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first_indexed 2021-11-25T10:06:19Z
last_indexed 2021-11-26T04:16:59Z
id cronfa58780
recordtype RisThesis
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spelling 2021-11-25T10:47:59.5961686 v2 58780 2021-11-25 Thermo-mechanical fatigue crack growth behaviour of Ti-6246 0cef97cdd2e8e6390ba82fdb4e38e3b6 JENNIE PALMER JENNIE PALMER true false 2021-11-25 Within the gas turbine engine, the high transient thermal stresses developed due to variations in power requirements during a typical flight cycle give rise to the phenomenon of thermo-mechanical fatigue (TMF). Associated with higher operating temperatures, the study of TMF within the gas turbine engine has mainly been focused on materials used in the latter turbine sections. However, the increasing temperatures to improve operating efficiency have led to the requirements for an understanding of the TMF behaviour in materials used for the later stages of the compressor. As such, fatigue crack growth rates are required to be evaluated under non-isothermal conditions along with the development of a detailed understanding of related failure mechanisms. In the current study a bespoke TMF crack growth (TMFCG) test set up has been developed and validated to investigate the TMFCG behaviour of the titanium alloy, Ti-6246. The study has explored the effects of phasing between mechanical loading and temperature, as well as the effects of maximum cycle temperature. Results show in-phase (IP) test conditions to have faster crack growth rates than out-of-phase (OP) test conditions, due to increased temperature at peak stress and therefore increased time-dependent crack growth. Fractography evidences subtle differences in fracture mechanisms and the microstructural analysis along the crack path has aided the characterisation of damage mechanisms in IP and OP test conditions. E-Thesis Swansea TMF, Titanium, Crack Growth 25 11 2021 2021-11-25 10.23889/SUthesis.58780 A selection of third party content is redacted or is partially redacted from this thesis due to copyright restrictions. COLLEGE NANME COLLEGE CODE Swansea University Whittaker, Mark ; Williams, Steve Doctoral EngD EPSRC, Rolls-Royce plc. 2021-11-25T10:47:59.5961686 2021-11-25T09:54:25.8776492 College of Engineering Engineering JENNIE PALMER 1 Under embargo Under embargo 2021-11-25T10:35:14.9910146 Output 14481492 application/pdf Redacted version - open access true 2025-12-16T00:00:00.0000000 Copyright: The author, Jennie Palmer, 2021. true eng
title Thermo-mechanical fatigue crack growth behaviour of Ti-6246
spellingShingle Thermo-mechanical fatigue crack growth behaviour of Ti-6246
JENNIE PALMER
title_short Thermo-mechanical fatigue crack growth behaviour of Ti-6246
title_full Thermo-mechanical fatigue crack growth behaviour of Ti-6246
title_fullStr Thermo-mechanical fatigue crack growth behaviour of Ti-6246
title_full_unstemmed Thermo-mechanical fatigue crack growth behaviour of Ti-6246
title_sort Thermo-mechanical fatigue crack growth behaviour of Ti-6246
author_id_str_mv 0cef97cdd2e8e6390ba82fdb4e38e3b6
author_id_fullname_str_mv 0cef97cdd2e8e6390ba82fdb4e38e3b6_***_JENNIE PALMER
author JENNIE PALMER
author2 JENNIE PALMER
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doi_str_mv 10.23889/SUthesis.58780
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hierarchy_parent_id collegeofengineering
hierarchy_parent_title College of Engineering
department_str Engineering{{{_:::_}}}College of Engineering{{{_:::_}}}Engineering
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description Within the gas turbine engine, the high transient thermal stresses developed due to variations in power requirements during a typical flight cycle give rise to the phenomenon of thermo-mechanical fatigue (TMF). Associated with higher operating temperatures, the study of TMF within the gas turbine engine has mainly been focused on materials used in the latter turbine sections. However, the increasing temperatures to improve operating efficiency have led to the requirements for an understanding of the TMF behaviour in materials used for the later stages of the compressor. As such, fatigue crack growth rates are required to be evaluated under non-isothermal conditions along with the development of a detailed understanding of related failure mechanisms. In the current study a bespoke TMF crack growth (TMFCG) test set up has been developed and validated to investigate the TMFCG behaviour of the titanium alloy, Ti-6246. The study has explored the effects of phasing between mechanical loading and temperature, as well as the effects of maximum cycle temperature. Results show in-phase (IP) test conditions to have faster crack growth rates than out-of-phase (OP) test conditions, due to increased temperature at peak stress and therefore increased time-dependent crack growth. Fractography evidences subtle differences in fracture mechanisms and the microstructural analysis along the crack path has aided the characterisation of damage mechanisms in IP and OP test conditions.
published_date 2021-11-25T04:15:40Z
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score 10.898525