Evolution of texture in Zr and Ti grain-refined by ECAP

Equal channel angular pressing (ECAP) was employed to grain refine Zr702 and CP Ti and the texture evolution during deformation was analyzed. With a use of die of 90 /20 in the intersection angles it was possible to refine the initial grain size of about 20 μm to about 250 nm at 350 C. The common feature of crystal rotation during ECAP was such that the left angle 11 anti 20 right angle direction of the basal plane as well as that of the prism planes aligned with the maximum shear direction on the shear plane of specimen. Activation of the primary slip systems and the resultant texture characteristics were independent to the initial textures, which were radically different in the two materials. In case of CP Ti a possible activation of twinning was also detected. Therefore the large plastic strain during ECAP of these two hcp metals was accommodated mostly by the left angle a right angle slips on the dual slip planes and in part by twinning. (orig.)