Edge dislocations in crystal structures considered as traveling waves of discrete models

Abstract

The static stress needed to depin a 2D edge dislocation, the lower dynamic stress needed to keep it moving, its velocity and displacement vector profile are calculated from first principles. We use a simplified discrete model whose far field distortion tensor decays algebraically with distance as in the usual elasticity. An analytical description of dislocation depinning in the strongly overdamped case (including the effect of fluctuations) is also given. A set of $N$ parallel edge dislocations whose centers are far from each other can depin a given one provided $N=O(L)$, where $L$ is the average inter-dislocation distance divided by the Burgers vector of a single dislocation. Then a limiting dislocation density can be defined and calculated in simple cases.