Destabilization of dislocation dipole at high velocity

Abstract

Under mechanical deformation of very high strain rates, it is expected that dislocations may move very fast (being subsonic, transonic, or even supersonic). As a result, two dislocations may approach each other at high velocities. Our earlier analyses of linear elasticity indicate that a dipole is destabilized when the approaching velocity is high enough—even below the speed of sound. In this letter, using the molecular dynamics method, we demonstrate that a dipole indeed can be destabilized above a critical velocity, and stable below that.