Hot forging characteristic of Ti-5Al-5V-5Mo-3Cr alloy with single metastable β microstructure

Hot deformation characteristic of Ti-5Al-5V-5Mo-3Cr alloy with a starting microstructure of an equiaxed single β microstructure is examined in relation to microstructural evolution and the result according to processing map technique. In testing at 700 °C, subgrain formation is dominant at higher strain rate, while superplasticity occurs at lower strain rate. Herein, dynamic α precipitation from supersaturated β phase occurs during deformation and affects the flow behavior. In testing at and above 800 °C, dynamic recovery (DRV) is dominant and continuous dynamic recrystallization (CDRX) also occurs especially in the vicinity of boundaries of prior-β-grains. There are three domains having an optimized power dissipation efficiency (ranging from 40% to 50%) in processing map. These three domains are reasonably explained in relation to microstructural conversion of frequent activations of grain boundary sliding, dynamic recovery and simultaneous occurrence of dynamic recovery and continuous dynamic recrystallization.