Atomistic simulation of the pinning of edge dislocations in Ni by Ni3Al precipitates

Classical molecular dynamics simulations of the interaction of edge dislocations in Ni with chains of spherical Ni3Al precipitates are performed using EAM potentials. The order hardening is investigated at temperature T = 0  K by determining the critical resolved shear stresses (CRSSs) for a superdislocation that is dissociated into four partial dislocations. The CRSS is computed as a function of the radius and the distance of the precipitates. It is found that for precipitates with a diameter smaller than the dissociation width of perfect edge dislocation in Ni, the CRSS of the trailing dislocation of the superdislocation is a fraction of about 0.4 of the CRSS of the leading dislocation.