Lattice orientation effect on the nanovoid growth in copper under shock loading

Abstract

Molecular-dynamics (MD) simulations have revealed that under shock loading a nanovoid in copper grows to be of ellipsoidal shape and different loading directions ([100] and [11̅ 1]) change the orientation of its major axis. This anisotropic growth is caused by preferential shear dislocation loop emission from the equator of the void under [100] loading and preferential shear dislocation loop emission deviating away from the equator under [11̅ 1] loading. A two-dimensional stress model has been proposed to explain the anisotropic plasticity. It is found that the loading direction changes the distribution of the resolved shear stress along the slip plane around the void and induces different dislocation emission mechanisms.