The Peierls-Nabarro model was extended so as to eliminate the so-called continuum approximation for the misfit energy, and was used to analyze the evolution of the dislocation core structure under glide and Escaig stress conditions. It was shown that the core could adopt competing multiple structures, with a marked dependence upon the dislocation axis position. It was demonstrated, for ordinary dislocations in the ordered L10 phase, as calculated by using ab initio generalized stacking fault energies, that these lattice discreteness effects (which were missing from the original Peierls-Nabarro model) significantly affected the evolution of dislocations under stress. Such effects could result in a ladder-like dependence of the partial separation under Escaig stress conditions, and lead to marked changes in the shape and amplitude of the Peierls barrier. It was concluded that lattice discreteness effects could be significant in ordered alloys having a deep Peierls valley. These effects resulted in an evolution of the dislocation structure which was more complex than previously thought.

Complex Evolution of Dislocation Core Structure in a Process of Motion - Model Analysis with ab initio Parameterization. O.N.Mryasov, Y.N.Gornostyrev, M.Van Schilfgaarde, A.J.Freeman: Materials Science and Engineering A, 2001, 309-310, 138-41