Abstract
The friction stress τt to overcome concentrated solute ions by thermal activation process and the dragging stress τd to move with the solute atmosphere formed by diffusion are given for the edge dislocation in model crystals. The total resistance stress τr which is assumed to be τt+τd increases with increasing the dislocation velocity from zero once has the maximum, and shows the minimum τmin at the velocity vH and again increaes monotonicaly. The plateau stress is given approximately by τmin. The dislocations separate into high-speed dislocations with vH, and the density ρH, and low-speed dislocations with vL and ρL at τmin. The temperature dependences of vH, vL, ρH and ρL are given. In most region of the plateau, ρH<<ρL but ρHvH>>ρLvL. The serration (P–L effect) is mainly induced by the intermittent group motion of the high-speed dislocations.