Large-scale molecular dynamics simulations of nanocrystalline material were used to investigate the interaction between dislocations, emitted under an indenter, and a nearby grain-boundary network. It was shown that, when the indenter size was smaller than the grain size, the grain boundaries not only acted as sinks for dislocations but, depending upon their local structure and stress distribution, could also reflect or emit dislocations. The emission and absorption process was accompanied by local atomic activity which involved atomic shuffling and free-volume migration within the grain boundary region.

Interaction between Dislocations and Grain Boundaries under an Indenter – a Molecular Dynamics Simulation. A.Hasnaoui, P.M.Derlet, H.Van Swygenhoven: Acta Materialia, 2004, 52[8], 2251-8