<i>In Situ</i> Observation on the Deformation Behavior of Primary α-Ti in a Textured Ti-6Al-4V

The tensile deformation process and dislocation behavior of primary α-Ti of Ti-6Al-4V were studied by the in-situ tensile test combined with EBSD (electron backscatter diffraction). The initiation, evolution and distribution of dislocation slips at different strains were discussed. The results showed that the microtexture of the material had a significant influence on slip behavior. Typically, basal and prismatic slips initiated first, but the dominant slip type was related to the local texture characteristics. Sometimes, the basal and prismatic slips could still initiate when their Schmid factors were relatively low, while the pyramidal slips usually need a higher Schmid factor to initiate. With the increase of strain, the second slip system inside one grain was activated to accommodate the plastic deformation. When the deformation was localized in a specific microtextured region, basal slips were dominant, but eventually the crack initiated from the slip bands inside the grain.