PSI - Issue 57

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 57 (2024) 642–648 Structural Integrity Procedia 00 (2022) 000 – 000

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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 scientific committee of the Fatigue Design 2023 organizers 10.1016/j.prostr.2024.03.071 2452-3216 © 2023 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 scientific committee of the Fatigue Design 2023 organizers 1. Introduction Waspaloy (UNS N07001) is a precipitation hardenable nickel-base superalloy (58.1% Ni-19.05% Cr-3.13% Ti 1.35%Al) alloy strengthened by a combination of cold work and age hardening to form fine coherent precipitates [1]. The aged alloy contains spherical, coherent Ni 3 (Al, Ti) known as γ’ phase which has a face -centered cubic structure (Ll 2 crystal). The γ’ phase, is the main strengthening phase in the alloy [2] . The mechanical behavior of Waspaloy depends highly on the heat treatment i.e aging conditions that increase or decrease the precipitates size but also the volume faction f v . Order strengthening by γ’ precipitation is a consequence of the hindering effect that precipitates have on dislocation motion. The additional stress required for dislocations to bypass precipitates depends on the underlying escape mechanism. Four types of mechanisms are possible. Two of them are essentially athermal, namely 2452-3216 © 2023 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 scientific committee of the Fatigue Design 2023 organizers 1. Introduction Waspaloy (UNS N07001) is a precipitation hardenable nickel-base superalloy (58.1% Ni-19.05% Cr-3.13% Ti 1.35%Al) alloy strengthened by a combination of cold work and age hardening to form fine coherent precipitates [1]. The aged alloy contains spherical, coherent Ni 3 (Al, Ti) known as γ’ phase which has a face -centered cubic structure (Ll 2 crystal). The γ’ phase, is the main strengthening phase in the alloy [2] . The mechanical behavior of Waspaloy depends highly on the heat treatment i.e aging conditions that increase or decrease the precipitates size but also the volume faction f v . Order strengthening by γ’ precipitation is a consequence of the hindering effect that precipitates have on dislocation motion. The additional stress required for dislocations to bypass precipitates depends on the underlying escape mechanism. Four types of mechanisms are possible. Two of them are essentially athermal, namely © 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 scientific committee of the Fatigue Design 2023 organizers Abstract The effect of hydrogen on the cyclic deformation behavior of Waspaloy in two heat treatment conditions was assessed via low cycle fatigue tests. H-charged and non-charged samples of both heat treatments were cycled to saturation to facilitate a comparison of stress amplitude, back stress, effective stress and shear bands behavior. For both aging conditions (weak coupling domain), H charging leads to a significant reduction in the stress amplitude, which is supported by the decrease of the effective stress and an increase of the back stress. Atomic force microscopy and transmission electron microscopy of these samples revealed a decrease of the shear bands spacing, with a modification of the shear bands widths and the dislocation density in bands. This result suggests that hydrogen impacts the dislocations-precipitates interaction. Keywords: Waspaloy, Fatigue, Hydrogen embrittlement, Preciptate-dislocation interactions, Internal stress Abstract The effect of hydrogen on the cyclic deformation behavior of Waspaloy in two heat treatment conditions was assessed via low cycle fatigue tests. H-charged and non-charged samples of both heat treatments were cycled to saturation to facilitate a comparison of stress amplitude, back stress, effective stress and shear bands behavior. For both aging conditions (weak coupling domain), H charging leads to a significant reduction in the stress amplitude, which is supported by the decrease of the effective stress and an increase of the back stress. Atomic force microscopy and transmission electron microscopy of these samples revealed a decrease of the shear bands spacing, with a modification of the shear bands widths and the dislocation density in bands. This result suggests that hydrogen impacts the dislocations-precipitates interaction. Keywords: Waspaloy, Fatigue, Hydrogen embrittlement, Preciptate-dislocation interactions, Internal stress Fatigue Design 2023 (FatDes 2023) The combined effect of hydrogen and aging conditions on the cyclic behavior of a precipitation-hardened nickel-base superalloy A. Radi 1,2 , M. Risbet 1 , G. Henaff 2 , A. Oudriss 3 , X. Feaugas 3 , R.Chantalat 4 (1) Laboratoire Roberval de mécanique, Université de Technologie de Compiègne, Alliance Sorbonne universités, Compiègne Cedex, France (2) Institut Pprime UPR 3346 CNRS, Ensma Université de Poitiers, Futuroscope Chasseneuil, France (3) LaSIE-CNRS UMR 7356, Université de La Rochelle, La Rochelle, France. (4) CETIM, pôle Fatigue Optimisation Durabilité, Senlis, France Fatigue Design 2023 (FatDes 2023) The combined effect of hydrogen and aging conditions on the cyclic behavior of a precipitation-hardened nickel-base superalloy A. Radi 1,2 , M. Risbet 1 , G. Henaff 2 , A. Oudriss 3 , X. Feaugas 3 , R.Chantalat 4 (1) Laboratoire Roberval de mécanique, Université de Technologie de Compiègne, Alliance Sorbonne universités, Compiègne Cedex, France (2) Institut Pprime UPR 3346 CNRS, Ensma Université de Poitiers, Futuroscope Chasseneuil, France (3) LaSIE-CNRS UMR 7356, Université de La Rochelle, La Rochelle, France. (4) CETIM, pôle Fatigue Optimisation Durabilité, Senlis, France