Thermally Activated Motion of Dislocations in a Field of Randomly Distributed Obstacles

A kinetic theory of dislocation motion in dilute solid solutions, based on the method of distribution functions is presented. It is assumed that the dislocation interacts with only one obstacle at a time. The glide resistance and the restoring force are rederived in a simple and transparent way. It is shown that the glide resistance may be obtained in the form of a friction stress, the friction coefficient in general being a function of stress. While analytical solutions to the kinetic equations are not obtainable in closed form the friction concept is shown to provide a fruitful basis for various approximations. The present treatment removes the inconsistencies of a previous theory by Labusch.