Anisotropic yielding behavior of rolling textured high purity titanium

The yield strength of rolling textured high purity α-Ti was found to be significantly dependent on the loading direction, i.e., yielding anisotropy; normal direction (ND)>transverse direction (TD)>rolling direction (RD). Activation stresses for three important deformation modes (prismatic, basal, and pyramidal 〈a〉 slips) were calculated based on the Schmid factor (SF) and effective critical resolved shear stress. The calculation result revealed that the specific crystallographic orientation of the material, caused by rolling texture, influences the activity of each deformation mode by affecting the SF and this significantly varies with the loading direction, thereby inducing a change of a deformation mode dominating the material yielding. Prismatic 〈a〉 slip governed the yielding in the RD and TD, while basal 〈a〉 slip was responsible for the yielding in the ND.