Atomic displacements accompanying deformation twinning: shears and shuffles

Abstract

Deformation twins grow by the motion of disconnections along their interfaces, thereby coupling shear with migration. Atomic-scale simulations of this mechanism have advanced to the point where the trajectory of each atom can be followed as it transits from a site in the shrinking grain, through the interface, and onwards to a site in the growing twin. Historically, such trajectories have been factorised into shear and shuffle components according to some defined convention. In the present article, we introduce a method of factorisation consistent with disconnection motion. This procedure is illustrated for the case of (Formula presented.) twinning in hexagonal close-packed materials, and shown to agree with simulated atomic trajectories for Zr. IMPACT STATEMENT Shear and shuffle displacements accompanying ((Formula presented.)) twinning are quantified consistently with growth by the observed mechanism of disconnection motion. This advance will facilitate the understanding of twinning kinetics.