Thermally Assisted Unpinning of a Dislocation Double Loop

Abstract
The effect of thermal fluctuations on dislocation unpinning is computed for a model case of a crystal containing dislocation double loops. The amplitude‐dependent decrement as a function of strain amplitude, temperature, and frequency is found to have a maximum. The form of the resulting theory is the same as that for the zero‐temperature theory, except that the mechanical breakaway stress of the zero‐point theory has to be replaced by a temperature‐ and frequency‐dependent thermal breakaway stress at finite temperatures.