The effect of Nb on the hydrogen embrittlement susceptibility of Q&P steel under static and dynamic loading

Journal article (2022)

Authors

F. Vercruysse Universiteit Gent
Lisa Claeys Universiteit Gent
Tom Depover Universiteit Gent
P. Verleysen Universiteit Gent
R.H. Petrov Universiteit Gent, Team Kevin Rossi - Mechanical, Maritime and Materials Engineering
Kim Verbeken Universiteit Gent
Research Group
Team Kevin Rossi (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2022 Florian Vercruysse, Lisa Claeys, Tom Depover, Patricia Verleysen, R.H. Petrov, Kim Verbeken
DOI
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https://doi.org/10.1016/j.msea.2022.143652
Martensitic transformation Dynamic loading Hydrogen embrittlement Niobium alloying Q&P steel
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Published Date

2022

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Materials Science and Engineering

Research Group

Team Kevin Rossi

Abstract

In the present study, the effect of Niobium (Nb) on the hydrogen embrittlement resistance of Quenched and Partitioning (Q&P) steel is investigated. For this purpose, the hydrogen uptake level and its impact on the mechanical properties of a Nb-free and a 0.024 wt% Nb Q&P steel are thoroughly analysed. The hydrogen trapping capacity is evaluated via thermal desorption spectroscopy (TDS). In-depth analysis of the desorption kinetics at different heating rates allows identification and quantification of the available trapping sites. The hydrogen embrittlement sensitivity of both steels is characterized using static and dynamic tensile tests. The addition of Nb results in an increase of the hydrogen concentration by more than 25%. The larger hydrogen content in the Nb steel, as a result of the higher fraction of grain boundaries/interphases, gives rise to a more severe embrittlement of the Nb steel compared to the Nb-free one. In addition to the larger hydrogen fraction in the Nb Q&P steel, the larger retained austenite fraction of low stability is detrimental due to the larger fraction of high carbon martensite formed when straining. This results in higher susceptibility to hydrogen embrittlement of the Nb microalloyed steel due to the brittle character of the high carbon martensite that forms easily during straining. Under dynamic loading conditions, the hydrogen embrittlement of both steels is minimal, which is attributed to a reduced hydrogen diffusion and the suppression of the transformation induced plasticity (TRIP) effect due to adiabatic heating.