Weak-beam study of the dislocation microstructure of β-CuZn deformed in the temperature domain of the plastic anomaly

Abstract

In the general framework of studies of the anomalous increase in plastic strength with temperature which is common to a number of ordered alloys, the effect of test temperature on the deformation microstructure has been investigated in β-CuZn (B2 structure). Single crystals have been deformed in compression at different temperatures between room temperature and 200[ddot]C along axes near [001] and [111]. The deformation microstructure has been observed under weak-beam conditions. The superdislocations with Burgers vector a<111> dissociated into two superpartials bounding an antiphase boundary (APB) have been found to dominate the microstructure over the whole temperature range although, in the near [111] orientation of the applied stress, deformation involves glide in the a<001> direction at the peak temperature. The relative density of climb-dissociated dislocations with mixed character has been observed to increase with temperature. In addition, the energies of the APBs on {110} and {112} planes have been measured at room temperature.