HIGH-TEMPERATURE DEFORMATION OF TITANIUM ALUMINIDE ALLOYS

The high-temperature deformation characteristics of Ti-xAl (x = 41, 45 , 52 at.%) alloys at 1200-1300 degrees C and effective strain rates of 10(-3)-10(-1) s(-1) with (cast + HIPed) and (cast + HIPed + forged) s tarting microstructures were studied to understand the deformation of two-phase gamma + alpha(2) alloys in terms of the deformation characte ristics of individual phases. No one mechanism predominates in the def ormation of these alloys. Dynamic recovery operates mainly at high tem perature, at low strain rate and in forged microstructure. Dynamic rec rystallization operates at low temperature, at high strain rate and in got microstructure. Increasing now stress is prevalent only in forged Ti-52Al and at low strain rates. A simple rule-of-mixtures model is in adequate to explain the deformation of Ti-48Al in terms of its constue nt phases.