Microstructure of hot-pack rolled Ti-43Al-9V-0.3Y alloy

A kind of Ti-43Al-9V-0.3Y alloy sheet material using hot-pack rolling method is prepared. The microstructures of this alloy containing alpha2/gamma lamellar microstructure, B-2 phases and rare earth phases (YAl2) are investigated. The results show that the hot-rolled process can breakdown the as-cast structure, and a fine and homogeneous microstructure can be obtained after hot-rolling. The grains under the as-rolled condition are elongated in the rolling direction and flattened in the normal direction of the sheet. It is very likely that the mechanism for this change in grain size and shape is a grain boundary bulging of deformed grains rather than the nucleation and growth of new recrystallized grains. Subsequent heat treatment at 1260 degreesC for 1 h and ageing at 1000 degreesC for 4 h will lead to grain growth, and the average grain size of as-rolled Ti-43Al-9V-0.3Y alloy is about 100 mum after heat treatment.