Interaction between dislocations and grain boundaries under an indenter – a molecular dynamics simulation

Large-scale molecular dynamics simulations of nanocrystalline Au are used to investigate the interaction between dislocations emitted under an indenter and the nearby grain boundary network. It is shown that for cases where the indenter size is smaller than the grain size, grain boundaries not only act as a sink for dislocations, but that depending on their local structure and stress distribution, they can also reflect or emit dislocations. The emission and absorption process is accompanied by local atomic activity involving atomic shuffling and free volume migration within the grain boundary region.