Influence of Forging Temperature on Microstructure and Tensile StrengthAeolotropy of TA15 Titanium Alloy

TA15 titanium alloy bars were fored in (α+β) phase region, and the effect of three forging temperatures, namely t_β-15℃, t_β-30℃ and t_β-50℃ (t_β was β phase transition temperature), on the microstructure and tensile strength aeolotropy of the alloy was investigated. The results show that with the decrease of forging temperature, the content of primary α_p phase in the TA15 titanium alloy increased while that of lamellar α phase decreased, and the thickness and aspect ratio of lamellar α phase decreased; therefore the tensile strength increased. After forging at T_β-50℃, the tensile strength along the streamline direction of the TA15 titanium alloy reached 973 MPa. The tensile strength difference in three directions decreased with decreasing forging temperature. The tensile fracture of the forged TA15 titanium alloy was ductile fracture. The lower the forging temperature, the higher the content of primary α_p phase, the deeper the dimples on fractures; when more slender lamellar α phases existed, the fracture dimples were shallower.