PSI - Issue 68

ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 68 (2025) 297–302

European Conference on Fracture 2024 Effect of microstructure on creep mechanical behavior and damage mechanisms of AISI 316L (N) austenitic stainless steels Marwa Ben Bettaieb a,b, *, Alexandra Renault-Laborne a , Sylvain Depinoy b , Ludovic Vincent a , Thilo F. Morgeneyer b a Université Paris-Saclay, CEA, Service de Recherche en Matériaux et procédés Avancés, 91191, Gif-sur-Yvette, France b MINES Paris, PSL University, MAT-Centre des Matériaux, CNRS UMR 7633, BP 87 91003 Evry, France Abstract The designation AISI 316L (N) regroups different materials that, depending on slight modifications of their chemical composition or on their manufacturing route, may develop different creep mechanical behavior and damage mechanisms. In this article, two AISI 316L (N) alloys are compared: a rolled plate and a niobium (Nb) rich hot forged thick plate. Both materials are submitted to the same creep conditions, 575 °C and 310 MPa. Due to a lower yield stress, the tensile strain at the end of the loading phase is higher for the Nb-rich alloy than for the rolled material. On the contrary, the subsequent creep strain rate and creep ductility are significantly lower for the Nb containing steel. The creep lifetime of the Nb-rich material is far longer than the one of the rolled Nb-free plate. Multiple internal crack initiations occur preferentially at the grain boundaries for both materials, but crack propagation eventually becomes mostly transgranular in the highly deformed rolled plate material while staying intergranular in the Nb-containing thick plate. Niobium carbonitrides and subgrain boundaries are revealed at the as-received state of the Nb-rich alloy. After this creep test, microstructural evolutions are only noticed in the Nb-free alloy. © 2025 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 ECF24 organizers Keywords: AISI 316L(N) austenitic stainless steel; Niobium (Nb); Creep; minimum creep rate; creep lifetime. European Conference on Fracture 2024 Effect of microstructure on creep mechanical behavior and damage mechanisms of AISI 316L (N) austenitic stainless steels Marwa Ben Bettaieb a,b, *, Alexandra Renault-Laborne a , Sylvain Depinoy b , Ludovic Vincent a , Thilo F. Morgeneyer b a Université Paris-Saclay, CEA, Service de Recherche en Matériaux et procédés Avancés, 91191, Gif-sur-Yvette, France b MINES Paris, PSL University, MAT-Centre des Matériaux, CNRS UMR 7633, BP 87 91003 Evry, France Abstract The designation AISI 316L (N) regroups different materials that, depending on slight modifications of their chemical composition or on their manufacturing route, may develop different creep mechanical behavior and damage mechanisms. In this article, two AISI 316L (N) alloys are compared: a rolled plate and a niobium (Nb) rich hot forged thick plate. Both materials are submitted to the same creep conditions, 575 °C and 310 MPa. Due to a lower yield stress, the tensile strain at the end of the loading phase is higher for the Nb-rich alloy than for the rolled material. On the contrary, the subsequent creep strain rate and creep ductility are significantly lower for the Nb containing steel. The creep lifetime of the Nb-rich material is far longer than the one of the rolled Nb-free plate. Multiple internal crack initiations occur preferentially at the grain boundaries for both materials, but crack propagation eventually becomes mostly transgranular in the highly deformed rolled plate material while staying intergranular in the Nb-containing thick plate. Niobium carbonitrides and subgrain boundaries are revealed at the as-received state of the Nb-rich alloy. After this creep test, microstructural evolutions are only noticed in the Nb-free alloy. © 2025 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 ECF24 organizers Keywords: AISI 316L(N) austenitic stainless steel; Niobium (Nb); Creep; minimum creep rate; creep lifetime. © 2025 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 ECF24 organizers

* Corresponding author. E-mail address: marwa.benbettaieb@cea.fr * Corresponding author. E-mail address: marwa.benbettaieb@cea.fr

2452-3216 © 2025 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 ECF24 organizers 2452-3216 © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.057