Temperature Dependence of Deformation Behaviour and Dislocation Structure of Al67Mn8Ti26 L12 Intermetallic Alloy

The Al3Ti-based L12 alloy Al67Mn8Ti25 shows different temperature dependence of the yield stress and ductility from that of the model L12 alloy Ni3Al. The dislocation structures and dissociation modes of the alloy deformed at room temperature, 673 and 873K were investigated by TEM. It is determined that at room-temperature and 673K, a<110> dislocation dissociated into two a/3<112> superpartials with SISF between them on {111} plane, while at 873K, the dissociation is a/2<110> pairs on {111} planes separated by APB. The temperature dependence of yield stress and ductility may be related to the dislocation structures at various temperatures.