Study of high-temperature deformation behavior and thermal processing diagram of cast TA15 titanium alloy

In this study, the high-temperature deformation behavior of cast TA15 titanium alloy was investigated by thermal simulation compression experiments. The heat deformation tempera-tures ranged from 1323 to 1473 K, and the strain rates were 0.1, 1.0, and 10 s-1. The results show that the softening mechanism of cast TA15 titanium alloy is mainly local plastic flow when deformed at a high strain rate (epsilon = 10 s-1); at a low strain rate (epsilon <= 1.0 s-1), it is mainly dynamic reversion and dynamic recrystallization. The developed constitutive equation that takes into account the effects of strain can accurately describe the rheological behavior of TA15 alloy over the entire stress range. The correlation coefficient r of 0.95637 and the average relative error ARE of 6.45 % were calculated between the flow stress values of the alloy during thermal deformation and the calculated values of the model, indicating that the model constructed in this study is more accurate. The optimal high-temperature deformation processing window was obtained using the thermal processing diagram and combined with the microstructure of the deformed specimens: deformation temperature 1373-1423 K and strain rate 0.1-1.0 s-1.