PSI - Issue 60

Available online at www.sciencedirect.com StructuralIntegrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 60 (2024) 444–455

© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Abstract The present study aims to understand the influence of prior fatigue loading on the tensile flow behaviour of austenitic 316L(N) stainless steel. The steel specimens were subjected to prior fatigue damage up to various fatigue life fractions. i.e., 5, 10, 30 and 50% of the fatigue life at a strain amplitude of ±0.6% and a nominal strain rate of 3×10 -3 s -1 and 300, 823 and 873 K. Subsequently the specimens were subjected to tensile deformation at the above temperature and strain rate and the tensile flow behaviour was evaluated in terms of Hollomon, Swift, Ludwigson and Voce equations. At 300 K, the flow curves of the specimens of as-received, and prior fatigue damaged were well described by the Ludwigson equation, whereas at 823 and 873 K, both Voce and Ludwigson equation could be used to describe the flow behaviour of the specimens. Increase of work hardening with the increase in prior fatigue damage at 823 and 873 K is attributed to the occurrence of dynamic strain ageing (DSA). At 300 K, a three-stage work hardening behaviour with a prominent stage II athermal hardening was observed for all the specimens, whereas at higher temperatures, only the as-received specimen exhibited the three-stage work hardening behaviour. At 823 and 873 K, a two-stage work hardening behaviour, comprising of a transient stage followed by stage III was observed for the specimens subjected to prior fatigue damage up to various fatigue life fractions. The inter relationship between the work hardening parameters of Ludwigson was rationalised in terms of the linearly inverse relationship between the work hardening rate and plastic strain rates. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Keywords: 316L(N) SS; DSA; Prior fatigue damage; Work hardening behaviour Third International Conference on Structural Integrity 2023 (ICONS 2023) Influence of Prior Fatigue Damage on Tensile Flow Behaviour of Type 316L(N) Austenitic Stainless Steel K. Mariappan a , E. Isaac Samuel a, *, Vani Shankar a,b and A. Nagesha a,b a Mechanical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, 603102, India b Homi Bhabha National Institute, Mumbai, Maharashtra, 400094, India

* Corresponding author. Tel.: +91 44 27480500 (Extn. 21172). E-mail address: isaac@igcar.gov.in

2452-3216© 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers 10.1016/j.prostr.2024.05.065