It was recalled that, within the general framework of non-linear elasticity, a subtle effect of plasticity had been observed in alloys at room temperature. This was the gliding instability of dislocations near to axi-symmetrical precipitates. It was explained by means of static atomistic simulations. It was demonstrated that the usually-neglected interaction between 3 sources (dislocations, external applied strain, precipitates) of strain was responsible for an unusual localized cross-slip of dislocations, from {111} to {100} planes, in zones with the axis of the precipitates. Static atomistic simulations, performed at 0K, clearly showed that modification of the interplanar distance in the neighbourhood of the precipitates, leading to a local modification of the shearing properties, was the cause of the gliding in {100} planes, observed in AA6056 (Al-Mg-Si) alloys. It was also believed that the third-order interaction described here played a key role in problems such as the creep of solids under irradiation.

Non-Linear Elastic Effects in Plasticity - {100} Dislocation Gliding in Aluminum-Based Alloy. J.Colin, P.Beauchamp, S.Brochard, J.Grilhé, A.Coujou: European Physics Letters, 2007, 78[1], 16002 (4pp)