Investigation of quasi-cleavage in a hydrogen charged maraging stainless steel

• Main Authors: Bestautte, Jolan, Kalácska, Szilvia, Béchet, Denis, Obadia, Zacharie, Christien, Frederic
• Format: Journal Article
• Language: English
• Published: 20-11-2022
• Subjects: Physics - Materials Science
• DOI: 10.48550/arxiv.2211.10918

Slow strain rates tests (SSRT) were conducted on hydrogen-containing
specimens of PH13-8Mo maraging stainless steel. Hydrogen-assisted subcritical
quasi-cleavage cracking was shown to take place during SSRT, thus accelerating
material failure. Fractographic analysis showed that quasi-cleavage is composed
of flat brittle areas and rougher areas. Using cross-sectional electron
backscatter diffraction (EBSD) analysis of a secondary subcritically grown
crack, we observed brittle cracks propagated across martensite blocks ahead the
main crack tip. These cracks were stopped at high-angle boundaries. The crack
direction was consistent with propagation along {100} type planes.
High-resolution EBSD showed significant crystal lattice rotation, hence
consequential plastic deformation, concentrated between the main crack tip and
the cracks located ahead it. It is concluded that quasi-cleavage in the
material investigated here consists of {100} cleavage cracks connected by
ductile ridges. A discontinuous mechanism, involving re-initiation of new
cleavage cracks ahead the main crack tip is suggested.