Deformation Structures of Pure Titanium during Shear Deformation

The deformation microstructure of commercial pure (CP) titanium formed in the theoretical shear zone of an equal channel angular pressing (ECAP) die during 3 or 4 passes is investigated by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The typical feature of the microstructure is that ultrafine grains coexist with coarse elongated grains with a high density of low-angle grain boundaries (LAGBs). Dislocation tangle zones (DTZs), dislocation cells (DCs), and subgrains are generated during shear deformation. The primary twin type has been found to be Grain refinement appears to progress by continuous dynamic recrystallization (CDRX), in which dislocation movement to LAGBs leads to their evolution into high-angle grain boundaries (HAGBs).