Mechanistic basis of temperature-dependent dwell fatigue in titanium alloys
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Accepted version
Published version
Author(s)
Zheng, Z
Balint, D
Dunne, F
Type
Journal Article
Abstract
The temperature-dependent dwell sensitivity of Ti-6242 and Ti-6246 alloys has been assessed over a temperature range from −50∘C to 390 °C using discrete dislocation plasticity which incorporates both thermal activation of dislocation escape from obstacles and slip transfer across grain boundaries. The worst-case load shedding in Ti-6242 alloy is found to be at or close to 120 °C under dwell fatigue loading, which diminishes and vanishes at temperatures lower than −50∘C or higher than 230 °C. Load shedding behaviour is predicted to occur in alloy Ti-6246 also but over a range of higher temperatures which are outside those relevant to in-service conditions. The key controlling dislocation mechanism with respect to load shedding in titanium alloys, and its temperature sensitivity, is shown to be the time constant associated with the thermal activation of dislocation escape from obstacles, with respect to the stress dwell time. The mechanistic basis of load shedding and dwell sensitivity in dwell fatigue loading is presented and discussed in the context of experimental observations.
Date Issued
2017-07-11
Date Acceptance
2017-07-10
Citation
Journal of the Mechanics and Physics of Solids, 2017, 107, pp.185-203
ISSN
0022-5096
Publisher
Elsevier
Start Page
185
End Page
203
Journal / Book Title
Journal of the Mechanics and Physics of Solids
Volume
107
Copyright Statement
© 2017 The Authors. Published by Elsevier Ltd.
This is an open access article under the CC BY license.
(http://creativecommons.org/licenses/by/4.0/)
This is an open access article under the CC BY license.
(http://creativecommons.org/licenses/by/4.0/)
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/K034332/1
Subjects
01 Mathematical Sciences
02 Physical Sciences
09 Engineering
Mechanical Engineering & Transports
Publication Status
Published