The image force on a dislocation which was situated a few interatomic distances from the interface that separated 2 welded half-crystals was investigated by means of computer simulation. The 2 half-crystals had the body-centered cubic structure, and the same lattice parameters and orientation, but had differing elastic moduli. The dislocation had a ½<111> Burgers vector, and a screw nature. The interface lay along a {112}- or {110}-type plane; parallel to the dislocation. By using a Finnis-Sinclair type of potential for α-Fe, the total strain energy which was stored in the bicrystal was calculated as a function of the dislocation position; thus giving the image force by derivation. Modifications in lattice friction (Peierls stress), and changes in the dislocation core, were investigated in the neighbourhood of the interface. The results were compared with those previously obtained for the planar-core <100> screw dislocation. All of the simulation results were then compared with the predictions of the Peierls-Nabarro-based model of Pacheco and Mura. In spite of some limitations, it was shown that this model could be extended so as to derive a general law for the image force in the interface region; provided that some measure of core-width was introduced explicitly.

Image Force on a Dislocation in a BCC Bicrystal - Computer Investigation of Core Effects. P.Beauchamp, J.Lepinoux: Philosophical Magazine A, 2001, 81[5], 1187-205