Microstructure and Crystallography of α Phase Nucleated Dynamically during Thermo-Mechanical Treatments in Metastable β Titanium Alloy

The α phase nucleated dynamically during the thermo–mechanical coupling process in titanium alloy is really interesting but difficult to sufficiently ascertain. In the present work, the α phase nucleation behavior, the orientation relationship between α/β as well as the phase transformation kinetics during hot deformation of Ti-5553 alloy were investigated in-depth. Results reveal that the “necklace” microstructure formed. The Burgers orientation relationship between α/β phases has been destroyed gradually. The β → α phase transformation is obviously retarded during the hot compression due to the competitive effect of softening process (dynamic recovery/recrystallization). These results could provide valuable reference for process optimization and the microstructural evolution controlling.