Shock Waves and High-Strain-Rate Phenomena in Metals

Abstract

A theoretical framework elucidating the generation of shock-induced defects is presented. Three different mechanisms responsible for the generation of point, line, and planar defects (twins and stacking faults), respectively, are described. Dislocations are homogeneously nucleated at or slightly behind the shock front by the powerful deviatoric stresses generated by the shock pulse; they are accelerated by the residual deviatoric stresses either towards or away from the front. Dislocation dynamical considerations limit their velocity to the velocity of shear waves in the medium. Their self-energy and stiffness are very high at the high velocities; hence, their ability to generate point defects upon intersecting each other is greatly enhanced, because the drag stress produced by the jogs is essentially independent of the velocity.