We have performed massively parallel 3D molecular dynamics simulations with up to 35 million atoms to investigate ductile failure, obtaining mechanistic information at the atomistic level inaccessible to experiment. We observe dislocation loops emitted from the crack front—the first time this has been seen in computer simulations. The sequence of dislocation emission events, essential for establishing an intrinsic ductility criterion, strongly depends on the crystallographic orientation of the crack front and differs strikingly from anything previously conjectured.

• Received 28 June 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.479