The temperature-dependence of the strength of the L12-structured compound was investigated in compression at temperatures of between -196 and 1200C. Below room temperature, the strength decreased with increasing temperature. An anomalous temperature-dependence of the strength was observed between room temperature and 800C; where the strength increased with increasing temperature. At temperatures above 800C, the strength again decreased with increasing temperature. The Burgers vectors of the dislocations in samples which had been deformed at room temperature, 600 or 1200C were investigated by using dark-field weak-beam imaging techniques and the equi-thickness fringe method of transmission electron microscopy. It was found that the a<¯110>-type super-dislocations dissociated into a/3<¯211>-type super-partial dislocations, which bounded a superlattice intrinsic stacking fault, in samples that had been deformed at 600 or 1200C. Dissociation of the antiphase boundary bounding-dislocation was not observed at any deformation temperature.

Temperature Dependence of the Flow Stress in Ir3Nb with the L12 Structure. Y.Yamabe-Mitarai, M.H.Hong, Y.Ro, H.Harada: Philosophical Magazine Letters, 1999, 79[9], 673-82