Hot deformation behavior and microstructure evolution of Ti2AlNb-based alloy in α2+B2 phase region

摘要

The hot deformation behavior of Ti-22Al-24Nb alloy at temperatures of 900~1050°C and a strain rate of 0.01-10s~(-1) as well as the microstructure evolution of the α2+B2 phase region were investigated by a Gleeble-3500 thermal simulation tester. The influence of strain rate and deformed temperature on the hot deformation of microstructure and the flow stress curve characteristics of the alloy were analyzed. The results show that the strain rate and deformed temperature have a great influence on the flow stress of Ti-22Al-24Nb alloy. When the strain rate is 1.0s~(-1), the peak stress increases gradually with the decrease of deformed ? temperature, and the deformed temperature is 930°C. The peak stress decreases as the strain rate decreases, and the flow stress curve of the alloy has the characteristics of stress peak, flow softening, and steady-state flow, deformed temperature and strain rate have a great influence on the α2+B2 phase region. When deformed at high strain rates( ε. ≥ 1.0s~(-1)), the microstructure of the alloy is prone to local plastic flow and adiabatic shear. When the deformation was carried out at low strain rate(ε ≤0.1s~(-1)), the local plastic flow and adiabatic shear characteristics did not appear in the alloy structure. With the increase of deformed temperature, the dynamic