Through-Thickness Variations of Deformed and Annealed Microstructures in ECAE-Processed Copper

Through-thickness variations of the microstructure in copper processed using equal channel angular extrusion (ECAE) to a strain of ~10 without rotations between passes have been investigated in deformed and partially recrystallized conditions. It is found that the through-thickness heterogeneity in the deformed sample follows the distribution of strain imposed by ECAE, where lower strain is imparted to the material that passes through the outer die corner. Also, the macroscopic distribution of recrystallized grains as a function of depth in the billet is found to be in correspondence to the applied strain. Compared to other inspected layers the bottom part of the billet was less refined after ECAE and remained less recrystallized after annealing.