The equilibrium shape and motion of a dislocation loop on a 2-dimensional periodic potential field were considered. The Peierls stress for a straight dislocation along non close-packed directions, as well as the Peierls stress for kink migration, could be neglected in comparison with that for a dislocation along close-packed directions; provided that the potential was not too high. A dislocation loop could take various stable forms under an applied stress of below a critical value. If the dynamic effect of the motion of a loop was taken into account, the segments along non close-packed directions - which started to move under small stresses - gained kinetic energy, and motion of segments along close-packed directions was produced. A reduction in the stress which was required for the infinite expansion of a loop could therefore occur.

Dynamic Expansion of a Dislocation Loop on a Two-Dimensional Periodic Potential. H.Koizumi, K.Ohno, T.Suzuki, F.R.N.Nabarro: Philosophical Magazine A, 1999, 79[2], 467-84