Anisotropic behavior and mechanical properties of Ti-6Al-4V alloy in high temperature deformation

Uniaxial hot tensile tests were carried out in the RD, 45°, and TD directions of cold-rolled Ti-6Al-4V alloy sheets. At 973 K-0.1 s−1, it shows apparent mechanical and fracture anisotropy. Increasing temperature or decreasing strain rate can reduce the anisotropic behavior and significantly improve its forming quality. The SEM-EBSD result indicates that there is a T-type texture in the initial microstructure. The yield anisotropy is closely related to the distribution of the Schmid factor caused by the texture. In the RD and 45° loading paths, the Schmid factors are large, and the basal and prismatic slip is easy to be activated. It is difficult to activate these two slip systems in the TD loading direction. Under high-temperature loading conditions, the rotation of grains leads to different orientation dispersion, which further affects the phase transformation and softening behavior. The primary mechanism affecting the softening behavior is dynamic recovery (DRV). In the case of the 45° loading direction, the orientation dispersion is the largest. Its DRV and phase transformation behavior is more prominent than the other two loading directions. The loading along 45° direction has the best forming quality, and it can be selected in the processing of Ti-6Al-4V alloy.