PSI - Issue 42

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ScienceDirect

Procedia Structural Integrity 42 (2022) 813–820 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

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© 2022 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 23 European Conference on Fracture – ECF23 From subsequent thermal desorption spectroscopy performed on the specimens after the permeation test, the hydrogen desorption spectra of Q&P steel samples show a high temperature peak which is not present in the spectrum of the unloaded sample. Thus indicating that the retained austenite is capable of trapping hydrogen in a loaded condition. Due to the di ff erence in matrix sur rounding the austenite phase, it is reasoned that the discrepancy in trapping behaviour is due to the internal stresses present in the austenite in Q&P steel and the higher hardness of the surrounding matrix compared to TRIP steel. c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) er-review under responsibility of 23 European Conference on Fracture – ECF23 . Keywords: Hydrogen trapping; Hydrogen di ff usion; Electrochemical hydrogen permeation; Retained austenite; Hydrogen embrittlement; Abstract This work investigates the e ff ect of a constant load on hydrogen di ff usion through transformation induced plasticity (TRIP)-assisted and quenching and partitioning (Q&P) steel containing metastable retained austenite by combining electrochemical hydrogen per meation and thermal desorption spectroscopy. Furthermore, a comparison is made with ferrite / martensite dual phase (DP) steel, which serves as a reference material not containing any retained austenite. Material samples are placed at di ff erent external loading conditions, ranging from 50% to 125% of the yield stress. The permeation transients indicate a di ff erent response between TRIP steel and Q&P steel. In the latter, hydrogen di ff usion is delayed for all stressed conditions, even at stresses in the elastic regime, whereas TRIP steels follows the same behaviour as the reference DP steel with increased hydrogen di ff usivity in the elastic regime and decreased in the plastic regime. From subsequent thermal desorption spectroscopy performed on the specimens after the permeation test, the hydrogen desorption spectra of Q&P steel samples show a high temperature peak which is not present in the spectrum of the unloaded sample. Thus indicating that the retained austenite is capable of trapping hydrogen in a loaded condition. Due to the di ff erence in matrix sur rounding the austenite phase, it is reasoned that the discrepancy in trapping behaviour is due to the internal stresses present in the austenite in Q&P steel and the higher hardness of the surrounding matrix compared to TRIP steel. c 2020 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 23 European Conference on Fracture – ECF23 . Keywords: Hydrogen trapping; Hydrogen di ff usion; Electrochemical hydrogen permeation; Retained austenite; Hydrogen embrittlement; 23 European Conference on Fracture – ECF23 The interaction of hydrogen with retained austenite in automotive steel grades Simon Vander Vennet a , Tom Depover a, ∗ , Kim Verbeken a, ∗ a Ghent University, Research group Sustainable Materials Science, Technologiepark 46, B-9052 Ghent, Belgium Abstract This work investigates the e ff ect of a constant load on hydrogen di ff usion through transformation induced plasticity (TRIP)-assisted and quenching and partitioning (Q&P) steel containing metastable retained austenite by combining electrochemical hydrogen per meation and thermal desorption spectroscopy. Furthermore, a comparison is made with ferrite / martensite dual phase (DP) steel, which serves as a reference material not containing any retained austenite. Material samples are placed at di ff erent external loading conditions, ranging from 50% to 125% of the yield stress. The permeation transients indicate a di ff erent response between TRIP steel and Q&P steel. In the latter, hydrogen di ff usion is delayed for all stressed conditions, even at stresses in the elastic regime, whereas TRIP steels follows the same behaviour as the reference DP steel with increased hydrogen di ff usivity in the elastic regime and decreased in the plastic regime. 23 European Conference on Fracture – ECF23 The interaction of hydrogen with retained austenite in automotive steel grades Simon Vander Vennet a , Tom Depover a, ∗ , Kim Verbeken a, ∗ a Ghent University, Research group Sustainable Materials Science, Technologiepark 46, B-9052 Ghent, Belgium

1. Introduction 1. Introduction

Quenching & Partitioning (Q&P) steels are part of the third generation advanced high strength steels (AHSS) and the particular heat treatment was proposed by Edmonds et al. (2006) as an alternative to transformation induced plasticity (TRIP)-assisted and dual phase (DP) steel in automotive applications. The quenching and partitioning heat treatment results in a final microstructure of intercritical ferrite ( α ) (Wang et al. (2018)), martensite ( α ) and austenite ( γ ) with a significantly increased carbon content compared to the matrix (Speer et al. (2003)). The increased Quenching & Partitioning (Q&P) steels are part of the third generation advanced high strength steels (AHSS) and the particular heat treatment was proposed by Edmonds et al. (2006) as an alternative to transformation induced plasticity (TRIP)-assisted and dual phase (DP) steel in automotive applications. The quenching and partitioning heat treatment results in a final microstructure of intercritical ferrite ( α ) (Wang et al. (2018)), martensite ( α ) and austenite ( γ ) with a significantly increased carbon content compared to the matrix (Speer et al. (2003)). The increased

2452-3216 © 2022 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 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.103 ∗ Corresponding authors. Tel. TD: + 32 9 331 04 38; KV: + 32 9 331 04 53 E-mail address: Tom.Depover@ugent.be; Kim.Verbeken@ugent.be 2210-7843 c 2020 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 23 European Conference on Fracture – ECF23 . ∗ Corresponding authors. Tel. TD: + 32 9 331 04 38; KV: + 32 9 331 04 53 E-mail address: Tom.Depover@ugent.be; Kim.Verbeken@ugent.be 2210-7843 c 2020 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 23 European Conference on Fracture – ECF23 .