Effect of the dislocations on the kinetics of a martensitic transition: MD simulation of bcc–hcp transformation in Zr

Abstract

Kinetics of the bcc→hcp transition in Zr is investigated by molecular dynamic (MD) simulation in the presence of dislocations. It is shown that the dislocations essentially stimulates the martensitic transformation by inducing a specific type of lattice instability. As a result, the transition near a dislocation becomes possible at much lower temperatures than in the ideal crystal. The transition occurs in two stages, a relatively long stage of a modulation of long-wavelength acoustic phonons, and a fast stage of short-wavelength phonon instability. Finally, the twin domains are formed with habit plane parallel to {1 1 0} bcc.