Effect of strain on diffusion kinetics and activation energy for al grain-boundary diffusion: A computer simulation

Abstract

The effect of strain on grain-boundary diffusion has been evaluated by molecular dynamics simulations. The system studied was a tilt boundary in a fee bicrystal model with interatomic potential calculated by the Embedded Atom Method. The results confirm the dominance of vacancy jump mechanism in grain-boundary diffusion even with up to 1.0% dilation strain at elevated temperatures. Vacancy jumps confine mostly to within the grain-boundary core. The jump direction is preferentially along the tilt axis. The simulations have yielded, as functions of strain, reasonable values of vacancy formation and migration energies. The relation between diffusivity and atomic mean-square displacement has also been examined and used to calculate grain-boundary diffusivity.