Towards a better understanding of hydrogen-assisted cracking in multiphase stainless steel.

Given the high strength of multiphase stainless steel, it is imperative to study its hydrogen embrittlement behavior. However, the understanding of hydrogen-assisted crack initiation and propagation is limited. In this study, we investigate the hydrogen-assisted cracking behavior of multiphase stainless steel through crack analysis, hydrogen permeation test, and hydrogen desorption experiments. Our findings reveal that hydrogen-assisted cracks initiate at the martensite packet boundaries and propagate along the packet boundaries, block boundaries, prior austenite grain boundaries and through ferrite. Additionally, we have elucidated the hydrogen trap sources and proposed a hydrogen-assisted cracking mechanism. • Hydrogen-assisted crack initiates at martensite packet boundaries. • Hydrogen-assisted crack extends in a mode of cleavage, quasi-cleavage, and IG. • Three groups of hydrogen traps have been analyzed in MPSS. • Hydrogen-assisted cracking mechanism of MPSS is proposed. [ABSTRACT FROM AUTHOR]