Mechanical tests were performed, on polycrystalline samples of a -phase alloy, at temperatures of between -150 and 1000C. Microstructural analysis clearly identified 3 temperature domains, which corresponded to differing deformation mechanisms. At low temperatures, the motion of super-dislocations which dragged faulted dipoles was rate controlling. At intermediate temperatures, where a stress anomaly was observed, simple screw dislocations with cusps were observed. The density of the latter increased with increasing temperature. A description of simple dislocation motion was developed on the basis of these observations. The glide of a simple screw dislocation in 2 planes, via a Peierls mechanism, was suggested to be the intrinsic source for the formation of pinning points. It was proposed that these pinning points could be erased by the lateral motion of super-kinks (unzipping process). The climb of simple dislocations appeared to control deformation at high temperatures.

B.Viguier, K.J.Hemker, J.Bonneville, F.Louchet, J.L.Martin: Philosophical Magazine A, 1995, 71[6], 1295-312