Effects of Elastic Anisotropy on the Anomalous Yield Behavior of Cubic Ordered Alloys

摘要

The positive temperature dependence of yield stress in certain Ll sub 2 and B2 alloys, e.g. Ni sub 3 Al and beta '-CuZn, is analyzed on the basis of the nature of dislocation dissociations predicted by anisotropic elasticity theory. In the case of Ni sub 3 Al, the torque due to the tangential component of the elastic interaction between two superpartials as a major driving force for either the cross-slip pinning model or the force couplet model. The corresponding torque term is relatively unimportant in the B2 structure. The core transformation of individual superpartials may be important for the anomalous increase of yield stress in beta '-CuZn. (ERA citation 12:018519)