The development of hardness homogeneity in a Cu-Zr alloy processed by equal-channel angular pressing

Experiments were conducted on a Cu-0.1% Zr alloy to evaluate the potential for achieving homogeneity when processing by equal-channel angular pressing (ECAP). Billets of the alloy were processed by ECAP for up to 8 passes at room temperature using a die with a channel angle of 110°. This processing reduced the grain size from an initial value of ∼30 μm to a value of ∼500 nm after 8 passes. Values of the Vickers microhardness were recorded on both the cross-sectional or X planes and the longitudinal or Y planes after ECAP. The results reveal the presence of lower hardness values adjacent to the lower surfaces of the billets in the early stages of processing but there is an evolution towards a hardness homogeneity throughout the billets after pressing through 8 passes. The measurements show this evolution occurs at similar rates on the X and Y planes.