Variant selection of α phase in TWIP Ti[sbnd]15Mo alloy by ball rolling

Abstract

Based on the morphology of α phase in the β-type Ti15Mo alloy with {332}<113>twinning-induced plasticity (TWIP) effect after ball rolling and aging, the variant selection of α phase was systematically analyzed from the aspects of deformation processes and lattice defects. The stress field generated by deformation as well as phase transformation and slip bands affected the variant selection of plate-like α phase in the β matrix, respectively. The film-like α phase with a single variant on the twin boundary was associated with the growth direction of the {332} twin. There were also plate-like α phase with different variants at different nucleation sites around the {332}<113> twin. The variant selection of the plate-like α phase nucleating directly on the film-like α phase and on the interface between the film-like α phase and the matrix was related to the film-like α phase. The variant selection of the plate-like α phase growing around the twin was affected not only by the geometrically necessary dislocations due to the twin-twin intersection, but also by the dislocation loops due to stress-induced ω phase.