It was recalled that, on the basis of classical dislocation theory, solid-solution hardening was usually attributed to the pinning of edge dislocations. At the atomic level, the theoretical study of dislocation cores questioned this prediction. Using static molecular simulations, with some interatomic effective potentials, it was demonstrated numerically that the critical resolved shear stress associated with a screw dislocation in a random Ni-Al single crystal was of the same order as that for the edge one. This result was imposed by the details of the dislocation stacking fault and of the core dissociation into Shockley partials. The statistical theory of solid-solution hardening was used to predict analytically the data acquired by atomistic simulation of various Al concentrations.

Depinning Transition for a Screw Dislocation in a Model Solid Solution. S.Patinet, L.Proville: Physical Review B, 2008, 78[10], 104109