High-temperature deformation of titanium aluminide alloys

The high-temperature deformation characteristics of Ti-xAl (x = 41, 48, 52 at.%) alloys at 1200–1300 °C and effective strain rates of 10−3−10−1 s−1 with (cast + HIPed) and (cast + HIPed + forged) starting microstructures were studied to understand the deformation of two-phase γ + α2 alloys in terms of the deformation characteristics of individual phases. No one mechanism predominates in the deformation of these alloys. Dynamic recovery operates mainly at high temperature, at low strain rate and in forged microstructure. Dynamic recrystallization operates at low temperature, at high strain rate and ingot microstructure. Increasing flow stress is prevalent only in forged Ti-52Al and at low strain rates. A simple rule-of-mixtures model is inadequate to explain the deformation of Ti-48Al in terms of its constituent phases.