Plastic deformation is an important process in the industrial production of polycrystalline pure
titanium and titanium alloy. The change of grain orientation and the formation of texture during the deformation process have important effects on the anisotropy. The crystallographic mechanism of plastic deformation of titanium is complex, involving basal plane slip, cylindrical slip, various cone slip and mechanical twinage. Currently, many popular crystallographic theories to describe plastic deformation of metals are mostly based on Taylor principle, including ALAMEL(Advanced Lamel) model, GIA (Grain Interaction) model, VPSC (Viscoplastic Self-consistent) model, etc. According to the original Taylor theory, each grain strain tensor is consistent with the shape strain tensor of the sample, which can guarantee the continuity of strain between polycrystalline grains, but not the continuity of stress. Currently, the model based on the principle of Taylor have generally realized the stress and strain at the same time continuous, however after experimental observation found that plastic deformation polycrystal strain tensor of each grain is often different from the sample macro strain tensor, although the strain gap between experimental observation and theoretical simulation is not big, but the gap means crystallography in the process of deformation mechanism is different, and may cause significant differences in the evolution of the orientation, lower texture prediction accuracy. It can be seen that various plastic deformation theories still need to be improved and perfected.
