A comparative study of dislocation core structures was conducted on a series of B2 compounds. The cores were studied using atomistic computer simulations with embedded-atom method potentials. The results revealed a strong dependence of the core structure upon the values of the antiphase boundary energies of the compounds. The <111> screw dislocations were found to have planar cores in {110} planes. The cores were very compact for very high antiphase boundary energies. As these energies decreased, an increasingly 2-dimensional spreading of the cores occurred and the dislocation eventually dissociated into partials. These partials were not exactly ½<111>, but corresponded to minima in the γ-surfaces of the compounds. The observed dislocation cores were best described as being partly dissociated into partials, with a continuous transition from dissociated to undissociated structures occurring as the planar fault energy increased. This was contrary to the view that dislocations were distinctly dissociated or undissociated.

Transition from Dislocation Core Spreading to Dislocation Dissociation in a Series of B2 Compounds. C.Vailhe, D.Farkas: Philosophical Magazine A, 1999, 79[4], 921-31