Non-radial interaction forces between superpartials in B2 and L1₂ ordered alloys

Abstract

Tangential interaction forces acting between superlattice partial dislocations in the L1₂ ordered alloys affect decisively the cross-slip of the dislocations and are thus a fundamental part of the models, explaining the so-called anomalous dependence of the flow stress with increasing temperature. A complex nature of the interaction forces between the ½<111> superpartials in the B2 structure is analysed and compared with the ½<101> superpartials in the L1₂ structure for all the orientations of dislocation lines on the {101}, {121} and {111}, {010} glide planes respectively. The similarities and differences of the dislocation behaviour in the two superlattices studied are pointed out. The stable dissociation of the screw dislocations lies in B2 and L1₂ on the {121} and {010} planes, respectively, which are in both cases inclined to the {101} and {111} primary slip planes. The stable dissociation plane of the edge dislocations is again in both cases perpendicular to the Burgers vector. Consequences for dislocation motion following from the presented results are discussed.