Grain morphology and texture evolution of TC21 titanium alloy during annealing with different time

A homogeneous equiaxed-structure TC21 titanium alloy is hot rolled and annealed for different time ranging from 1 h to 6 h. The grain morphology and texture evolution of alpha and beta phases during annealing are mainly investigated using the electron back-scattered diffraction characterization. In the early annealing stage, the a grain mainly maintains the elongated morphology generated in the rolling. With increasing annealing time, more and more elongated a grains become equiaxed due to enhanced static recrystallization and boundary splitting. Differently, the beta grain exhibits a fully equiaxed morphology all the time due to the sufficient static recrystallization, and get a coarsening with increasing annealing time. The a phase exhibits a (0001) basal texture in the early annealing stage, and then forms alpha TD-split texture with increasing annealing time. The beta phase exhibits the {001}< 110 > texture at every annealing time. Based on the analysis about the texture of different grain sizes, the effects of recrystallization nucleation and oriented growth on texture evolution are discussed. It suggests that TD-split texture in a phase is originated from both the recrystallization nucleation and oriented growth. The formation of {001}< 110 > texture in beta phase is mainly originated from the oriented growth.