Plateau Stress, Thermally Activated Dislocation Motion and Solute Atmosphere Dragging in Concentrated KCl–KBr Solid Solution Single Crystals

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The friction stress τ t to overcome concentrated solute ions by thermal activation process and the dragging stress τ d to move with the solute atmosphere formed by diffusion are given for the edge dislocation in model crystals. The total resistance stress τ r which is assumed to be τ t +τ d increases with increasing the dislocation velocity from zero once has the maximum, and shows the minimum τ min at the velocity v H and again increaes monotonicaly. The plateau stress is given approximately by τ min . The dislocations separate into high-speed dislocations with v H and the density ρ H , and low-speed dislocations with v L and ρ L at τ min . The temperature dependences of v H , v L , ρ H and ρ L are given. In most region of the plateau, ρ H ≪ρ L but ρ H v H ≫ρ L v L . The serration (P-L effect) is mainly induced by the intermittent group motion of the high-speed dislocations.