Effects of temperature and surface step on the incipient plasticity in strained aluminium studied by atomistic simulations

Atomistic simulations using an EAM potential are carried out to investigate the first stages of plasticity in aluminium slabs, in particular the effect of both temperature and step geometry on the nucleation of dislocations from surface steps. Temperature is shown to significantly reduce the elastic limit, and to activate the nucleation of dislocation half-loops. Twinning occurs by successive nucleations in adjacent glide planes. The presence of a kinked step is shown to have no influence on the nucleation mechanisms.