Wear resistance of an ultrafine-grained Cu-Zr alloy processed by equal-channel angular pressing

A Cu-0.1 wt.% Zr alloy was processed by equal-channel angular pressing (ECAP) through 8 passes at room temperature to produce an ultrafine grain size of ~350 nm with an average Vickers microindentation hardness (200 gf) of ~140. Ball-on-disc dry sliding tests were conducted on an annealed material and on the ECAP-processed alloy using applied normal loads from 1 to 15 N. The coefficient of friction (COF), surface topography and wear volume loss were examined to evaluate the micro-wear resistance. The results show that samples processed by ECAP have lower average values for the COF than the unprocessed alloy and there is also a decrease in the wear depth and wear volume loss with increasing numbers of ECAP passes. The ultrafine-grained alloy processed by ECAP has a higher wear resistance than the annealed and unprocessed material due to the significant grain refinement and improved mechanical properties.