A novel semi-discrete Peierls–Nabarro model was introduced which could be used to study dislocation spreading at more than one slip plane, such as dislocation cross-slip and junctions. The strength of the model, when combined with an atomistic simulation for dislocation core properties, was without suffering from the uncertainties associated with empirical potentials. Therefore, this method was particularly useful in providing insight into alloy design when empirical potentials were not available or not reliable for such multi-element systems. The model was applied to study the external stress assisted dislocation cross-slip and constriction process in two face-centered cubic metals, Al and Ag, exhibiting different deformation properties. It was found that the screw dislocation in Al could cross-slip spontaneously in contrast with that in Ag, where the screw dislocation splits into two partials that cannot cross-slip without first being constricted. The dislocation response to an external stress was examined in detail. The dislocation constriction energy and the critical stress for cross-slip were determined, and from the latter, the cross-slip energy barrier for straight screw dislocations was estimated.

On Stress-Assisted Dislocation Constriction and Cross-Slip. G.Lu, V.V.Bulatov, N.Kioussis: International Journal of Plasticity, 2004, 20[3], 447-58