Micromechanical analysis of anisotropy and asymmetry in pure titanium using electron backscatter diffraction and crystal plasticity finite element modeling

Commercially pure titanium (CP Ti) with a hexagonal close-packed structure exhibits large anisotropy and asymmetry at room temperature. While several reasons have been put forth to explain such unique behavior, the deformation mechanism responsible for the observed anisotropy and asymmetric yielding and hardening is not clearly understood. In this study, to understand the deformation mechanism of CP Ti and investigate the origin of such unusual mechanical behavior, a micromechanical analysis was conducted using electron backscatter diffraction (EBSD) and crystal plasticity finite element analyses. Representative volume elements of titanium sheets were generated using statistical data related to the microstructure, as analyzed using EBSD. Crystal plasticity model parameters corresponding to different deformation modes, including prismatic, basal, pyramidal (c+a) slip, {1012} tensile twinning, and {1122} compressive twinning, were calibrated using the macroscopic behavior in various loading conditions. Finally, the roles of different deformation modes in dictating the anisotropic and asymmetric behavior of CP Ti are discussed.