The effect of synthetic driving force on the atomic mechanisms associated with grain boundary motion below the interface roughening temperature

The mechanisms associated with grain boundary motion induced by synthetic, crystal-orientation-dependent driving forces are investigated for a large-angle [0 0 1] Ni symmetric tilt grain boundary. The application of non-physical forces by this method brings legitimate concern that it could lead to non-physical results. This concern is especially relevant below the interface roughening transition temperature where there is a substantial drop in grain boundary mobility and large driving force dependence. Using slip-vector analysis and examining continuum metrics for microrotation and strain, this work shows that the application of synthetic-driving forces does not alter the fundamental mechanisms leading to grain boundary motion. Results in this work are compared directly to shear driven simulations which reveal that the path and deformation history of grain boundary motion is unbiased by the non-physical nature of the driving force acting on the boundary. Nudged elastic band calculations show that the transition path for grain boundary motion is independent of the driving force magnitude and the energy barriers for motion are not appreciably altered by the application of the synthetic driving force.