A Finnis-Sinclair type of interatomic potential was used to determine the properties of dissociated screw dislocations in a face-centred cubic lattice. The critical stress for dislocation motion was found to be a sensitive function of the partial dislocation separation; with a lower limit which was at least 85% smaller than the Peierls stress. The constriction of Heidenreich-Shockley partials was modelled by using an applied stress which interacted only with the edge Burgers vectors. Recombination was not observed, but there was a critical separation below which the potential energy of the dislocation rose very rapidly. The classical model of cross-slip, in which the dislocation could not leave its slip plane unless it was fully constricted, was found to be incorrect. Instead, cross-slip was possible at all partial separations; provided that the driving stress was large enough.

Dislocation Motion, Constriction and Cross-Slip in Face-Centered Cubic Metals. M.Duesbery: Modelling and Simulation in Materials Science and Engineering, 1998, 6[1], 35-49