Production of TiAl sheet with oriented lamellar microstructure by diffusional reaction of aluminum and textured titanium foils

The idea that the orientations of lamellar microstructure in the sheet of TiAl intermetallic compound can be controlled by achieving the textured alpha single phase state by the diffusional reaction of aluminum and textured titanium foils is experimentally examined. The reaction process was analyzed by DTA, EDX and texture measurements. It was found that the oriented lamellar microstructure can be constructed by the process consisting of four stages; transforming stage of the pure aluminum layer to Al3Ti for avoiding the formation of aluminum liquid phase, enriching stage of aluminum content in the titanium layer to prevent the alpha-beta transformation during the heating to alpha single phase state, heating stage to obtain a single phase stale and cooling stage to form the lamellar microstructure consisting of alpha(2) and gamma phases.