PSI - Issue 23

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Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 Structural Integrity Procedia 00 (2019) 000 – 000

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ScienceDirect

Procedia Structural Integrity 23 (2019) 275–280

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers © 201 9 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. The cyclic plasti response and damage evolution in high temperatur cycling with dwells and during thermomechanic l fatigue of superausteni ic teel Sanicro 25 has been studied. Fatigue harde ing/softening curves in cycling with dwells have been compared with thos in constant train rate cycling. Rapid hardening a d early saturation has been found i cycling with dwells. Study of the surface evolu ion using SEM observations and FIB cutting revealed the preferential oxidation grain bound ries wh ch were perpendicular to the stress axis. In roduction of dwells i maximum tension lead to the ope ing of the early cracks, their sliding and formation wedge cracks. Fatigue harde ing/softening curves in ther omechanical in-phase cycling do not exhibit s turatio th hardening is hi her tha in cons a t str in rate cycling. Damage mechanism was similar to that in isothermal cycling and even more damaging as found by plotting Manson-Coffin curves. © 201 9 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. 9th International Conference on Materials Structure and Micromechanics of Fracture Cyclic plastic response and damage in superaustenitic steel in high temperature cycling with dwells and in thermomechanical cycling Jaroslav Polák a,b * , Roman Petráš a,b a Institute of Physics of Materials ASCR, Žižkova 22, 616 62 Brno, Czech Republic b CEITEC, Institute of Physics of Materials ASCR, Žižkova 22, 616 62 Brno, Czech Republic 9th International Conference on Materials Structure and Micromechanics of Fracture Cyclic plastic response and damage in superaustenitic steel in high temperature cycling with dwells and in thermomechanical cycling Jaroslav Polák a,b * , Roman Petráš a,b a Institute of Physics of Materi ls ASCR, Žižkova 22, 616 2 Brno, Czech Republic b CEITEC, Institute of Physics of Materials ASCR, Žižkova 22, 616 62 Brno, Czech Republic Abstract Abstract The cyclic plastic response and damage evolution in high temperature cycling with dwells and during thermomechanical fatigue of superaustenitic steel Sanicro 25 has been studied. Fatigue hardening/softening curves in cycling with dwells have been compared with those in constant strain rate cycling. Rapid hardening and early saturation has been found in cycling with dwells. Study of the surface evolution using SEM observations and FIB cutting revealed the preferential oxidation of grain boundaries which were perpendicular to the stress axis. Introduction of dwells in maximum tension lead to the opening of the early cracks, their sliding and formation wedge cracks. Fatigue hardening/softening curves in thermomechanical in-phase cycling do not exhibit saturation and the hardening is higher than in constant strain rate cycling. Damage mechanism was similar to that in isothermal cycling and even more damaging as found by plotting Manson-Coffin curves. 1. Introduction To increase the efficiency of power plants materials for components of these plants must sustain higher temperatures under several service conditions. High temperatures and varying stresses induce appreciable damage and to secure the desired life of the whole system materials must be appropriately tested. Recently austenitic 1. Introduction To inc ase the fficiency of p wer plants mat rials for components of the plants must sustain higher temperatures und r s veral service conditi ns. High te p ratures and varying st esses induce appr ciable damage and to secure the desired life of the whole system materials must be appropriately tested. Recently austenitic Keywords: Sanicro 25; cyclic plasticity; fatigue damage; cycling with dwells; thermomechanical fatigue Keywords: Sanicro 25; cyclic plasticity; fatigue damage; cycling with dwells; thermomechanical fatigue

* Jaroslav Polák . Tel.: +420-532-290-366. E-mail address: polak@ipm.cz * Jaroslav Polák . Tel.: +420-532-290-366. E-mail address: polak@ipm.cz

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/)

Peer-review under responsibility of the scientific committee of the IC MSMF organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.099