Distribution of Dislocation-Twin Interaction in Twip Steel Under Different Loading Modes

Abstract

The tension-compression asymmetry and orientation effect of dislocation-twin boundary (TB) interactions in twinned TWIP steels were investigated using the discrete dislocation dynamics simulations and Schmid's law. The different types of dislocations dominate the TB migration in the twinned TWIP steel during tension and compression with the same loading orientation, and the asymmetric dislocation reactions at TB were attributed to the different leading partials produced after the dissociation of dislocation under different loading modes (tension or compression). Moreover, the complex dislocation-TB interactions, such as dislocations traversing TB, cross slip, dissociation, pile up and so on, were determined by considering the orientation effect of dislocation activation and the asymmetry of dislocation dissociation. The research advances the understanding of asymmetric behavior of twin and its influence on the macro hardening in plastic deformation of TWIP steels.

Keywords: Tension-compression asymmetry, Discrete dislocation dynamics, Dislocation-TB interactions, Orientation effect, TWIP steels.