Fluctuations of impurity composition and their role in dislocation cross slip in crystals

The influence of impurities on the kinetics of split-dislocation cross slip caused by a change in the stacking-fault energy is studied theoretically. It is shown that the fluctuations in the impurity composition of a crystal make a considerable contribution to the kinetics of dislocation cross slip. The activation-energy spectrum and the average frequency of the processes of dislocation cross slip are calculated for a model of random impurity distribution in a crystal. The calculation shows that the fluctuations in impurity concentration, reducing the stacking-fault energy, play an important role in the low-temperature region.