Shear Texture Formation during High-Strain Torsion of Titanium Aluminides

Abstract

Ti-47Al-4(Cr, Nb, Mn, B) samples with different initial grain structures and fibre textures were deformed in torsion at 1000 °C under hydrostatic pressure of 400 MPa in a Paterson type rock deformation machine at a maximum constant strain rate of 2*10-4 s-1. The microstructure was investigated by transmission electron microscopy (TEM). Local texture measurements as a function of shear strain were done with high-energy synchrotron radiation. During shearing due to dynamic recrystallization the initially lamellar structure breaks down into a fine-grained globular structure with a g grain size in the order of 5 µm. The shear texture developed consists of <110> and {110} inclined to the shear direction and shear plane, respectively. The microstructure and texture development is discussed.