Characterization of hot deformation behavior of as-forged TiAl alloy

The deformation behavior of as-forged Ti-43Al-9V-Y alloy was investigated by hot compression tests in the temperature range of 1100-1225 °C and strain rate range of 0.01-0.5 s−1. The results show that the alloy exhibits negative temperature sensitivity and positive strain rate sensitivity. The stress exponent (n = 3.02) and the apparent activation energy (Q = 342.27 kJ/mol) of the present alloy are lower than that of previous reported TiAl alloys, which suggests that the as-forged Ti-43Al-9V-Y alloy exhibits better deformability at low temperatures and high strain rates. A processing map for hot working was developed on the basis of a dynamic material model. The deformation mechanisms were analyzed by the processing map. The optimum processing condition at the strain of 0.6 is 1180-1210 °C/0.01-0.05 s−1. A crack-free Ti-43Al-9V-Y sheet was prepared by hot rolling at these optimized parameters. EBSD results show that dynamic recrystallization is more likely to occur for γ phase.