Atomic-scale computations were made of the static de-pinning threshold of dislocations in Al(Mg) solid solutions. The interaction between the dislocations and the isolated obstacles was studied for different types of obstacle, i.e. single solute atoms situated at different positions, and solute dimers with different bond directions. Part of this work was used to apply different standard analytical theories for solid solution hardening, the predictions of which were finally compared with the present direct atomic-scale simulations for dislocation de-pinning in random Al(Mg) solid solutions. According to the present comparisons, the dislocation statistics in the present atomic-scale simulations was qualitatively well described by the Mott–Nabarro–Labusch theory. In agreement with earlier results for a different system, Ni(Al), the de-pinning thresholds were similar for the edge and screw dislocations.

Dislocation Pinning by Substitutional Impurities in an Atomic-Scale Model for Al(Mg) Solid Solutions. S.Patinet, L.Proville: Philosophical Magazine, 2011, 91[11], 1581-606