The formation of microtextured region during thermo-mechanical processing in a near-β titanium alloy Ti-5Al-5Mo-5V-1Cr-1Fe

Electron backscatter diffraction (EBSD) and backscattered electron imaging (BSE) were used to study the origin of microtextured region and how thermo-mechanical processing affects the macro/microtexture in near-β titanium alloys. Multi-step heat treatments were conducted on an (α+β)-warm-compressed Ti-55511 bar. It includes two-step sub β-transus annealing (830 °C, 2 h, 750 °C, 2 h) and a sub β-transus aging (600 °C, 8 h). The results show that microtextured regions, consisted of similar-shaped αp+αs lamellae and αag platelets, formed after the final aging. By analyzing the α and β texture during each thermomechanical step, the microtextured region (macrozone) formation was related to the maintained Burgers Orientation Relationship between α/β. In addition, the variant selection mechanism also leads to microtexture development.