By using massively parallel molecular dynamics simulations of the evolution of a U-shaped dislocation in face-centered cubic Al, conventional and non-coplanar (in a helical form) evolution of dislocation segments was revealed at the atomistic scale. The two different forms were closely related to the Frank-Read multiplication mechanism. The possibility of non-coplanar process was quantitatively analyzed by using a combination of continuum dislocation dynamics theory and atomistic simulations. The cross-slip mechanism which was involved in the non-coplanar evolution was investigated by examining its energy barrier and critical stress. It was suggested that the development of the two different forms was dictated by the strain rate and the crystal size.

Atomistic Simulations for the Evolution of a U-Shaped Dislocation in FCC Al. X.Y.Li, W.Yang: Physical Review B, 2006, 74[14], 144108 (6pp)