Climb dissociation of 〈111〉 superdislocations in β-CuZn

Abstract

The core structure of 〈111〉 superdislocations in β-CuZn deformed at high temperatures has been studied in detail by weak-beam electron microscopy. It has been found that the two superpartials of the 〈111〉 superdislocations, both in edge and near-screw orientations, do not lie on the same glide plane. That is, the 〈111〉 superdislocations are climb-dissociated. The climb dissociation most likely takes place during glide motion, presumably as a result of interactions with vacancies. The transition of slip direction and the strength anomaly observed at around 200°C in β-CuZn can be explained by this mechanism.