An investigation of the deformation process during equal-channel angular pressing of an aluminum single crystal

This investigation examines the deformation process when an aluminum single crystal is subjected to equal-channel angular pressing (ECAP) using a die having a channel angle of 90°. The crystal within the entrance channel was oriented so that the {1 1 1} slip plane and the 〈1 1 0〉 slip direction were inclined at 20° in a counter-clockwise direction from the theoretical shear plane and the theoretical shear direction. The crystal was pressed through one pass at room temperature and then carefully examined. After passing through the shear plane, it is shown that the initial orientation remains in the upper portion of the specimen within the exit channel but there is a rotation by ∼60° in a counter-clockwise direction near the lower die wall. These observations show that shear occurs in the upper portion of the specimen but there is a rotation in the lower portion due to the arc of curvature at the outer point of intersection of the two channels.