Extensive parallel 3-dimensional molecular dynamics simulations, involving up to 35 million atoms, were used to obtain mechanistic information, on ductile failure at the atomistic level, which could not be revealed by experiment. For the first time in such simulations, dislocation loops were observed to be emitted from the crack front. It was found that the sequence of dislocation emission events, which was required in order to establish an intrinsic ductility criterion, depended strongly upon the crystallographic orientation of the crack front. The sequence differed markedly from all previous conjectures.

S.J.Zhou, D.M.Beazley, P.S.Lomdahl, B.L.Holian: Physical Review Letters, 1997, 78[3], 479-82