A Portevin-Le Chatelier Effect expected from Solute Atmosphere Dragging

Abstract A solute atmosphere, will be formed round a moving dislocation in a solid solution, when the dislocation velocity is smaller than the critical value for the case of solute atoms interacting hydrostatically with an edge dislocation, where A is a parameter indicating the strength of the interaction, b′ is a distance of the order of the interatomic one, and the other parameters have their usual meanings. There may exist another critical velocity (Cottrell 1953 a), v CH, which corresponds to the maximum drag stress due to the solute atmosphere. In the range of v CH < v < v CL, a moving dislocation will be subjected to a lower dragging stress with higher velocity. A kind of Portevin-Le Chatelier effect is expected from this dynamical instability of plasticity.