A Novel Computational Method of Processing Map for Ti-6Al-4V Alloy and Corresponding Microstructure Study

摘要

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.