Shock wave induced migration of an edge dislocation dipole in alpha-Fe

Abstract

The mobility of a 1∕2⟨111⟩{110} edge dipole in alpha-iron has been studied using molecular dynamics simulations. Collision cascades generated by keV recoils have been shown to induce the migration of dislocations. In order to elucidate the origin of the motion of these dislocations, and separate the production of defects from temperature or pressure effects, a stressed region of different shapes (sphere and cylinder) is simulated close to the edge dipole. We observe that the generated shock wave triggers the movement of the dislocations even when no defects are produced. The shape of the distorted region and the character of the dislocations influence the way the dislocations move, due to the change in Peach-Koehler force direction and to the fact that the shock waves arrive to the different parts of the dislocations at different times.