Study on the dynamic hot compression behavior and deformation mechanism of TA15 titanium alloy

To study the dynamic hot deformation behavior of TA15(Ti-6Al-2Zr-1Mo-1V) alloy, the hot compression experiments adopting cylindrical specimens at constant strain rates were executed on Gleeble-1500 simulator(deformation temperatures of 550-l000°C and strain rates of 0.01-1s^-1), the deformation activation energy Q was calculated and the hot deformation microstructure was observed. The results show that the flow stress decreases with deformation temperature rising and increases with strain rate growing. The flow deformation behavior could be divided into three types of working hardening (550-600°), dynamic recrystallization (650-900°C) and dynamic recovery (950-1000°C). The calculated deformation activation energy is 517 kJ/mol in (α+β) phase region and 205 kJ/mol in p phase region. The flow stress curves, deformation activation energy and deformation microstructure reveal that the main softening mechanism is dynamic recrystallization in (α+β) field and dynamic recovery in β field. As the strain rate declines the dynamic recrystallization proceeds more adequately in (α+β) region and the subgrain of dynamic recovery has the tendency to grow in β region.