Isothermal uniaxial compressions of a Ti-6Al-4V alloy were carried out in the temperature range of 800–1050 °C and strain rate range of 0.001–1 s⁻¹. The effects of friction between the specimen and anvils as well as the increase in temperature caused by the high strain rate deformation were considered, and flow curves were corrected as a result. Constitutive models were discussed based on the corrected flow curves. The correlation coefficient and average absolute relative error for the strain compensated Arrhenius-type constitutive model are 0.986 and 9.168%, respectively, while the values for a modified Johnson-Cook constitutive model are 0.924 and 22.673%, respectively. Therefore, the strain compensated Arrhenius-type constitutive model has a better prediction capability than a modified Johnson-Cook constitutive model.

The Arrhenius-type constitutive equation is mostly used to describe flow behaviors of material. However, no processing map has been constructed directly according to it. In this study, a novel computational method was applied for establishing the processing map for Ti-6Al-4V alloy in the temperature and strain rate range of 800–1050 °C and 0.001–10 s⁻¹, respectively. The processing map can be divided into four domains according to its graphic features. Among the four domains, the optimal domain is in the temperature and strain rate range of 850–925 °C and 0.001–0.1 s⁻¹, where peak efficiency η is 0.54 and the main microstructural evolution is DRX (dynamic recrystallization). When the alloy is processed in the α + β phase field, the temperature and strain rate range of 800–850 °C and 3–10 s⁻¹ should be avoided, where instability parameter ξ is negative and the microstructural feature is flow localization. When the alloy is processed in the β phase field, DRV (dynamic recovery) and slight DRX of β phase is the main microstructural characteristics in the range of 1000–1050 °C and 0.001–0.02 s⁻¹. However, flow localization of β phase is the main microstructural feature in the range of 1000–1050 °C and 1–10 s⁻¹, which should be avoided.

The microstructure and tensile properties of Ti-6Al-6V-2Sn alloy heat-treated at different solution and aging temperatures has been systematically investigated. Specimens were solution-treated at 970 °C (above the β transus) and 920 °C (below the β transus), respectively, followed by water quenching. When the alloy is quenched from 970 °C, α’ (hcp) and α˝ (orthorhombic) martensite phases co-exist in the microstructure. When it is quenched from 920 °C, α´ martensite phase does not form, while equiaxial primary α (α_p) phase and α˝ are found in the microstructure. The results also show that the strength of the alloy increases but the ductility deteriorates as the solution temperature becomes higher when the aging treatment is unchanged. This is because the volume fraction of equiaxial α_p phase is lower but the volume fraction of the acicular secondary α (α_s) phase is higher for higher solution temperature. When the alloy is aged at different temperatures after the solution treatment at 900 °C, the strength of the alloy decreases with the increase of aging temperature and the ductility shows the opposite trend as the size of the acicular α_s becomes longer and its volume fraction is lower at higher aging temperature.