Micromechanical mechanism of texture formation in γ-TiAl

Texture evolution in TiAl depends on the type of deformation such as uniaxial compression, tension or rolling as well as on the initial microstructure. Cast TiAl shows a lamellar microstructure with an alignment of the lamellae and exhibits a strong texture. Deformation parallel to the aligned lamellae results in a plane-strain deformation which leads to a brass type texture. From room temperature up to 700 °C, compression tests of TiAl specimens with equiaxed microstructures result in <110>-fiber textures where the <101> component is shifted to <302>. At higher temperatures the orientation <302> is caused by dynamic recrystallization. In rolled sheets of TiAl with equiaxed microstructure the main texture component is a modified cube texture {100}<010> where the tetragonal c-axis is aligned in transverse direction of the sheet. This texture component is caused by dynamic recrystallization and appears to be stable against further rolling.