Microstructure and tensile properties of a continuous-cast Al-Li-Hf alloy

The optical micrographs of the as-cast alloy showed columnar grain, elongated in the cast direction, and formed from the outer surface to the centre of ingot. Finer equiaxed grains were formed in the central part of the ingot. The MEB and MET micrographs showed that the microstructure of the as-cast alloy consisted mainly of granular α (Al-rich phase) grains containing colonies of dendrites or cells. These were outlined by a layer of solute-rich interdendritic zones.