Effects of Stacking Fault Energy on Fundamental Deformation Modes in Single Crystalline Magnesium by Molecular Dynamics Simulations

Abstract

In order to investigate effects of stacking fault energies (SFEs) on fundamental deformation modes of slips and deformation twinnings in magnesium, we carried out molecular dynamics simulations of shear deformations for the deformation modes with two kinds of many-body interatomic potentials. The SFEs of the basal and second-pyramidal planes are lower for a generalized embedded atom method (GEAM) potential than for an embedded atom method (EAM) potential. While the basal slip quite easily occurs and the prism dislocation is activated, the first-pyramidal slip and the second-pyramidal slip are hard to be operated. However, for the GEAM simulations, the second-pyramidal slip was activated due to reduction of the second-pyramidal SFE. Additionally, the reduction of the SFEs suppresses nucleation of the {10\bar{1}1} twin in the b₂^{10\bar{1}1} shearing direction. The relative order of the other fundamental deformation modes in the critical shear stress is qualitatively maintained despite the reduction of the SFEs.