LOW-TEMPERATURE SOFTENING IN BODY-CENTERED CUBIC ALLOYS

In the low-temperature range, bcc alloys exhibit a lower stress-temperature dependence than the pure base metals. This effect often leads to a phenomenon that is called ″alloy softening″ : at low temperatures, the yield stress of an alloy may be lower than that of the base metal. Various theories of alloy softening are reviewed; the most promising are based either on extrinsic or intrinsic models of low-temperature deformation. Some other aspects of alloy softening are discussed, among them the effects on the ductile-brittle transition temperature.