PSI - Issue 59

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

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ScienceDirect

Procedia Structural Integrity 59 (2024) 98–103

© 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 DMDP 2023 Organizers © 2024 The Auth ors. 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 DMDP 2023 Organizers Keywords: high-strength pearlitic steel; stress triaxiality; constraint; multiaxial stress states; hydrogen embrittlement; notch tensile strength; hydrogen assisted microdamage (HAMD); tearing topography surface (TTS); hydrogen damage topography (HDT). Abstract This paper analyzes the hydrogen assisted microdamage (HAMD) region in high-strength eutectoid pearlitic steel on the basis of slow strain rate tests (SSRT) on axisymmetric round-notched samples under hydrogen embrittlement environmental conditions. The use of very different notched specimens and their associated stress and strain distributions in the vicinity of the notch tip allows a study of local triaxiality effects on hydrogen embrittlement of the round notched samples, as well as the important role of the hydrostatic stress state on hydrogen diffusion and micro-cracking (or micro-damage). The microscopic appearance of the hydrogen-affected region – the so-called tearing topography surface (TTS) – resembles micro-damage, micro-cracking or micro tearing at a micro- or nano-scale due to hydrogen degradation , thereby affecting the notch tensile strength of the specimens and producing the phenomenon of hydrogen embrittlement/degradation. A micromechanical model is proposed to explain these hydrogen effects on the material on the basis of the lamellar micro- and nano-structure of the pearlitic steel under consideration. © 2024 The Auth ors. 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 DMDP 2023 Organizers Keywords: high-strength pearlitic steel; stress triaxiality; constraint; multiaxial stress states; hydrogen embrittlement; notch tensile strength; hydrogen assisted microdamage (HAMD); tearing topography surface (TTS); hydrogen damage topography (HDT). VII Internatio nal Conference “In -service Damage of Materials: Diagnostics and Prediction ” (DMDP 2023) Notch tip hydrogen assisted microdamage in fully pearlitic steel: The Tearing Topography Surface (TTS) Jesús Toribio* Fracture & Structural Integrity Research Group (FSIRG), University of Salamanca (USAL) E.P.S., Campus Viriato, Avda. Requejo 33, 49022 Zamora, Spain Abstract This paper analyzes the hydrogen assisted microdamage (HAMD) region in high-strength eutectoid pearlitic steel on the basis of slow strain rate tests (SSRT) on axisymmetric round-notched samples under hydrogen embrittlement environmental conditions. The use of very different notched specimens and their associated stress and strain distributions in the vicinity of the notch tip allows a study of local triaxiality effects on hydrogen embrittlement of the round notched samples, as well as the important role of the hydrostatic stress state on hydrogen diffusion and micro-cracking (or micro-damage). The microscopic appearance of the hydrogen-affected region – the so-called tearing topography surface (TTS) – resembles micro-damage, micro-cracking or micro tearing at a micro- or nano-scale due to hydrogen degradation , thereby affecting the notch tensile strength of the specimens and producing the phenomenon of hydrogen embrittlement/degradation. A micromechanical model is proposed to explain these hydrogen effects on the material on the basis of the lamellar micro- and nano-structure of the pearlitic steel under consideration. VII Internatio nal Conference “In -service Damage of Materials: Diagnostics and Prediction ” (DMDP 2023) Notch tip hydrogen assisted microdamage in fully pearlitic steel: The Tearing Topography Surface (TTS) Jesús Toribio* Fracture & Structural Integrity Research Group (FSIRG), University of Salamanca (USAL) E.P.S., Campus Viriato, Avda. Requejo 33, 49022 Zamora, Spain

* Corresponding author. Tel.: +34-677566723; fax: +34-980545002. E-mail address: toribio@usal.es * Corresponding author. Tel.: +34-677566723; fax: +34-980545002. E-mail address: toribio@usal.es

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 DMDP 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 DMDP 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 DMDP 2023 Organizers 10.1016/j.prostr.2024.04.015