Effects of hydrogen content that alters damage evolution mechanisms in SUH 660 precipitation-strengthened Fe–Cr–Ni steel

Abstract This study aims at understanding the change of the hydrogen embrittlement mechanism with respect to hydrogen content of a precipitation-strengthened Fe–Ni–Cr-based steel. Hydrogen was electrochemically introduced with different current densities. The hydrogen-charging deteriorated crack initiation and propagation resistances as well as the crack tip blunting capability. Further, with increasing hydrogen content, the primary cracking sites changed from coarse carbides to slip bands, and then to grain boundaries. Moreover, because the crack initiation probability increased and the resistance to trans-granular crack propagation decreased with hydrogen content, the crack coalescence associated with slip localization occurred more frequently.