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

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 degrees 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 degrees C and 0.001-0.1 s(-1), where peak efficiency eta is 0.54 and the main microstructural evolution is DRX (dynamic recrystallization). When the alloy is processed in the alpha + beta phase field, the temperature and strain rate range of 800-850 degrees C and 3-10 s(-1) should be avoided, where instability parameter sigma is negative and the microstructural feature is flow localization. When the alloy is processed in the beta phase field, DRV (dynamic recovery) and slight DRX of beta phase is the main microstructural characteristics in the range of 1000-1050 degrees C and 0.001-0.02 s(-1). However, flow localization of phase is the main microstructural feature in the range of 1000-1050 degrees C and 1-10 s(-1), which should be avoided.