Microstructure evolution and grain refinement mechanism of TC11 titanium alloy under ultrasonic vibration-assisted hot compression

In this paper, the microstructure evolution of TC11 titanium alloy in the process of ultrasonic vibration-assisted hot compression forming was studied. The results show that the microstructure of TC11 titanium alloy mainly characterized by changes in primary α phase morphology, size and content during hot compression. After ultrasonic vibration was applied, dynamic recrystallization (DRX) can be further promoted, and the area fraction of DRX increases from 20.7% to 36%. Ultrasonic vibration can promote the generation of high-angle boundaries (HABs) and make low-angle boundaries (LABs) transform into HABs. Due to the dual action of DRX and grain boudaries transformation, ultrasonic vibration can promote grain refinement, and the number of 3 μm–10 μm fine grains in the TC11 titanium alloy increases significantly.