A kinetic Monte Carlo algorithm was used to simulate the motion of ½<111>-oriented screw dislocation on a {011}-slip plane in body-centered cubic Ta and Ta-based alloys. The dislocation moved according to the kink model: double-kink nucleation, kink migration and kink–kink annihilation. The rates of these unit processes were parameterized on the basis of existing first-principles data. Both short-range (solute–dislocation core) and long-range (elastic misfit) interactions between the dislocations and solute were considered. Simulations were performed in order to determine the dislocation velocity as a function of stress, temperature, solute concentration, solute misfit and solute–core interaction strength. The dislocation velocity was shown to be controlled by the rate of nucleation of double kinks. The dependence of the double-kink nucleation rate upon stress and temperature were consistent with existing analytical predictions. In alloys, the dislocation velocity depended upon both the short- and long-range solute dislocation interactions as well as upon the solute concentration. The short-range solute–core interactions were shown to dominate the effects of alloying upon dislocation mobility. The present simulation method provided the critical link between atomistic calculations of fundamental dislocation and solute properties, and large-scale dislocation dynamics that usually involved empirical equations of motion.

Stochastic Simulation of Dislocation Glide in Tantalum and Ta-Based Alloys. C.S.Deo, D.J.Srolovitz, W.Cai, V.V.Bulatov: Journal of the Mechanics and Physics of Solids, 2005, 53[6], 1223-47