Orientation control of lamellar mictrostructure in TiAl intermetallic compound by reactive diffusion of aluminum and textured titanium foils and high-temperature deformation

Processes based on reactive diffusion and high temperature deformation in the two phase state are experimentally examined on Ti-43mol%Al and Ti-46mol%Al, in order to find the method to produce TiAl intermetallic compound with the oriented lamellar microstructure. The reactive diffusion process is to produce the a single phase state with orientations reflecting the texture of the starting titanium foils and the high temperature deformation aims at the rotation of lamellar interface by the preferential activation of the crystal slip systems parallel to the interface. It is found that the reactive diffusion process is effective to control the texture in the a single phase state, although many voids are formed at the initial stages of reactive diffusion. The uniaxial compression at 1323K after the heating for constructing lamellar microstructure is quite effective to rotate the lamellar interface parallel to the compression plane. About one half of the whole lamellae is arranged within 20 degrees from the compression plane by the deformation.