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

TL;DR

This study uses atomistic simulations to explore how temperature and surface step geometry influence the initial plastic deformation mechanisms in aluminum, revealing temperature's role in lowering elastic limits and promoting dislocation nucleation.

Contribution

It provides new insights into the effects of temperature and surface step geometry on dislocation nucleation and plasticity in aluminum at the atomic level.

Findings

Temperature reduces elastic limit and activates dislocation nucleation.

Twinning occurs via successive nucleations in adjacent planes.

Kinked steps do not affect nucleation mechanisms.

Abstract

Atomistic simulations using an EAM potential are carried out to investigate the first stages of plasticity in aluminum 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.