Deformation behavior of Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy with two initial microstructures during hot working

Abstract The effects of initial microstructure on the flow stress, strain rate sensitivity ( m ), strain hardening exponent ( n ), apparent activation energy ( Q ) for deformation of Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy were investigated using isothermal compression tests. Results show that the alloy with Widmanstatten alpha plates shows a higher peak stress and flow softening. Additionally, the alloy with equiaxed primary alpha exhibits an early yield drop at or above 810 °C and at strain rates of 0.1–5.0 s −1 . In the strain range of 0.5–0.7, m of the alloy with equiaxed primary alpha is found to be larger at 0.01 s −1 and lower deformation temperatures. This phenomenon could be reasonably explained based on the microstructure evolution. The strain has a significant effect on n of the alloy with Widmanstatten alpha plates, which is attributed to platelet bending/kinking and dynamic globularization of α phase. In the strain range of 0.15–0.55, Q of the alloy with Widmanstatten alpha plates is larger.