固溶时效工艺对Ti-6Al-6V-2Sn钛合金棒材组织及性能的影响

The influences of solution and aging treatment process on microstructure and properties of Ti-6Al-6V-2Sn alloy rods were investigated by using optical microscope (OM), XRD, scanning electron microscopy (SEM) and mechanical properties test. The results show that the as-forged microstructures of Ti-6Al-6V-2Sn alloy rods are fine isothermal primary α and transition β phases. After solution treatment, the microstructure is mainly composed of isothermal primary α_p, martensite α’, α″ and metastable β phases. The strength decreases, but the reduction of area increases, which indicates that the solution treatment has a softening effect. With the rise of solution temperature, the strength increases subsequently, and the plasticity decreases. And fine dispersion secondary α_s phase precipitates from the metastable structures after aging treatment process, the alloy can be strengthened significantly with slightly reduced plasticity. And with the aging temperature increases, the strengthening effect is reduced, and the plasticity increases. Through comprehensive comparison, considering the best match of the strength and plasticity, it can determined that the optimization solution and aging treatment process of Ti-6Al-6V-2Sn alloy in this experiment is (880 ℃, 1 h, WQ)+ (580 ℃, 4 h, AC).