Effect of Copper Content on the Mechanical and Tribological Properties of ZnAl27-Based Alloys

Abstract

One binary ZnAl27- and five ZnAl27-based ternary alloys containing 1–5% Cu were produced by permanent mould casting. Their friction and wear properties were examined using a block-on-ring test machine after determining their hardness and tensile strength. It was observed that the hardness and tensile strength of the ZnAl27-based ternary alloys increased with increasing copper content up to 2% due to solid-solution hardening, above which their tensile strength decreased, while hardness continued to increase. This is attributed to the formation of copper-rich e and T′ phases, which reduce the solid-solution hardening of the alloys. It was found that the wear volume loss of the ZnAl27-based alloys decreased with increasing copper content up to 2% but showed a small increase above this level. Therefore, it was concluded that the wear resistance of ZnAl27-based alloys containing 1 to 5% Cu correlates well with their tensile strength. In addition, smearing and scratches were found to be the main features of the wear surfaces of the ZnAl27-based alloys under static loading and lubricated sliding conditions.