Dynamic Globularization Mechanism in TC21 Titanium Alloy during Hot Rolling

摘要

The microstructure evolution of the α/β titanium alloy TC21 has been characterized with respect to the mechanisms of the dynamic and static globularization of the a phase. Hot rolling at strains of 0. 36,0. 69,and 1. 2 was performed at 900 °C. The results reveal that the globularization of the a phase, is not a nucleation-and-growth process. The boundary misorientation histogram is bimodal under all test conditions by electron backscatter diffraction. It is concluded that the mechanism of the globularization of the α lamellae is that subgrain boundaries are formed by geometric dynamic recrystallization,and then separation of α lamellae occur by β phase penetration.