Molecular dynamic simulations of plasticity and phase transition in Mg polycrystalline under shock compression

Abstract

We have investigated the shock-induced plasticity and phase transition in the hexagonal columnar nanocrystalline Mg by large-scale nonequilibrium molecular dynamics simulations. The preexisting grain boundaries (GBs) induce the nucleation of the {10–12} twins for the local stress relaxation. The twins grow up in grains leading to the orientation rotation. The phase transition from the hexagonal close-packed phase to the body-centered cubic phase begins when the migrating twin GBs meet in A- and C-type grains, and continues in the plastic deformation regions. The phase-transition pathway involves two steps: the reorientation and phase transformation.