In the general framework of non-linear elasticity, a subtle effect of plasticity recently observed in alloys at room temperature, i.e. the gliding instability of dislocations near to axisymmetrical precipitates, was explained by means of static atomistic simulations. It was demonstrated that the interaction usually neglected between three sources of strain identified as the dislocations, the external applied strain and the precipitates was responsible for the unusual localized cross-slip of the dislocations from the {111} to {100} planes in zone with the axis of the precipitates. The static atomistic simulations performed at 0K had clearly shown that the modification of the interplanar distance in the neighborhood of the precipitates leading to a local modification of the shearing properties was at the origin of this gliding in {100} planes recently observed in Al-Mg-Si alloys 6056. It was believed that the third-order interaction emphasized here played a key role in many other problems such as creep of solids under irradiation for example.

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