Microtexture evolution effected by Mo content in α + β titanium alloys

Abstract

Mo element significantly affects the microtexture evolution of α in α + β titanium alloys. In this study, the evolution of microtexture during thermomechanical processing in Ti-6Al-2Sn-4Zr-2Mo (Ti6242) and Ti-6Al-2Sn-4Zr-6Mo (Ti6246) alloy was investigated. The β annealing treatments and α + β solution-treatments were conducted to display the microstructure characteristics before thermal deformation. Then, the thermal compression in the (α + β) phase region was applied to trace the evolution of lamellae orientation in conjunction with the electron backscatter diffraction. The results show a strong prior colony microtexture before thermal deformation. {10−12} and {10−11} twins are activated in Ti6246 during thermal compression, which strongly weakens the microtexture of the prior α colony. Besides, the lower volume fraction of the primary α phase, the smaller α colony, the thinner lamellae and the lower aspect ratio of α grains contribute to weak prior colony microtexture in Ti6246 alloy. This study shows the effect of Mo content on the microtexture evolution during thermomechanical processing.