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

Atomistic Simulation of the Pinning of Edge Dislocations in Ni by Ni3Al Precipitates. Kohler, C., Kizler, P., Schmauder, S.: Materials Science and Engineering A, 2005, 400-401[1-2], 481-4