Mechanism of crack propagation due to hydrogen embrittlement in iron single crystals stressed along [001] axis

Abstract

Striation-like hydrogen embrittlement (SHE) fracture occurs at low hydrogen concentration for an iron single crystal with a small carbon content, while cleavage fracture occurs at higher hydrogen concentration. The cleavage fracture initiated owing to hydrogen accumulated in front of the SHE crack tip propagates extremely fast without plastic deformation. It is, however, under discussion whether a small amount of hydrogen causes lattice decohesion or not.