Influence of crystal orientation on ECAP of aluminum single crystals

A single crystal of high purity aluminum, oriented with the {1 1 1} slip plane and the 〈1 1 0〉 slip direction rotated by 20° in a clockwise sense from the theoretical shear plane and the shear direction, was processed by equal-channel angular pressing (ECAP) through a single pass. This configuration was designated the 20° orientation and the results are compared with earlier data obtained on a similar high purity aluminum single crystal in the 0° orientation with the (1 1 1) slip plane and the 〈1 1 0〉 slip direction lying parallel to the shear plane and the shear direction. The results show that in both orientations the long axes of the subgrains lie parallel to the slip traces of the primary ( 1 ¯   1 ¯   1 ¯ ) [ 1 ¯   1   0 ] slip system and the average subgrain widths are ∼1.3 μm. However, the shearing characteristics are different because the 0° specimen exhibited a conventional B-type rolling texture whereas the 20° specimen deformed by slip on the primary ( 1 ¯   1 ¯   1 ¯ ) [ 1 ¯   1   0 ] slip system and this system rotated by ∼40° in a counter-clockwise sense as the specimen passed through the shear zone of the ECAP die.