Microstructural Evolution in Gamma Titanium Aluminides During Severe Hot-Working

Abstract

The plastic anisotropy of the γ titanium aluminides leads to the formation of shear bands and textures during hot-working. The textures and shear bands are well developed during severe hot-working necessary to achieve well-consolidated microstructures. The underlying mechanisms and the resulting effects on the deformation behavior could thus be studied thoroughly. This was done by scanning electron microscopic, transmission electron microscopic, high-energy X-ray diffraction, and mechanical testing techniques. Accordingly, the plastic anisotropy of the lamellar structure causes the formation of shear bands. The subsequent deformation within the shear bands is then stabilized by recrystallization processes. The plastic anisotropy of the constituent phases, on the other hand, causes the formation of textures in accordance with the directional shear stresses induced by deformation resulting in anisotropic deformation characteristics.