Effects of Equal-Channel Angular Pressing on the Anisotropy of Ultrafine Copper and Titanium

Annealed commercially pure copper and titanium were processed by equal-channel angular pressing (ECAP) using routes BC and C. Pressed samples had a square section with a side length of 8 mm. Anisotropy was analyzed based on the conventional yield strength at compression in three mutually perpendicular directions. The tests were conducted with the as-received materials and after different number of ECAP passes. For copper, which is isotropic in the as-received state, considerable anisotropy manifests itself after the first pass and holds out after the subsequent passes. Anisotropy of as-received titanium holds out at further pressing and makes about 25 percent. Anisotropy after all the passes is similar both for room and elevated temperature. Anisotropy manifests itself during pressing in both routes, BC and C, although its behavior differs for the different routes.