Deformation induced kink band formation and ω-to-β phase reversion in a cold rolled metastable β Ti-10Mo alloy

The deformation mechanism of a metastable β Ti-10Mo (wt.%) alloy during cold rolling was investigated using scanning electron microscopy, transmission electron microscopy, and aberration-corrected scanning transmission electron microscopy. While being typically considered a TRIP alloy, {332} β β deformation twinning was identified as the dominant mechanism, accompanied by nanoscale stress-induced ω and αʺ martensite. Additionally, nanoscale β -type deformation induced kink bands formed via lattice rotation around β axis due to pileups of {112} β β dislocations, effectively relaxing localized strain. Inside primary deformation kink bands, secondary β -type kink bands developed together with ω-free zones, wherein pre-formed athermal ω reverted to β phase. It is speculated that {112} β β dislocation slip within primary kink bands promote secondary kink bands and facilitate the atomic shuffling along {112} β planes leading to the ω-to-β phase reversion. These findings provide new insights into the role of kink band formation in strain accommodation and phase reversion in ductile metastable β titanium alloys.