Micromechanical mechanism of texture formation in gamma-TiAl

Texture evolution in TiAl depends on the type of deformation such as uniaxi al compression, tension or rolling as well as on the initial microstructure . Cast TiAl shows a lamellar microstructure with an alignment of the lamell ae and exhibits a strong texture. Deformation parallel to the aligned lamel lae results in a plane-strain deformation which leads to a brass type textu re. From room temperature up to 700 degreesC, compression tests of TiAl spe cimens with equiaxed microstructures result in < 110 > -fiber textures wher e the < 101 > component is shifted to < 302 >. At higher temperatures the o rientation < 302 > is caused by dynamic recrystallization. In rolled sheets of TiAl with equiaxed microstructure the main texture component is a modif ied cube texture {100} < 010 > where the tetragonal c-axis is aligned in tr ansverse direction of the sheet. This texture component is caused by dynami c recrystallization and appears to be stable against further rolling. (C) 2 001 Elsevier Science Ltd. All rights reserved.