Microstructure, mechanical properties and sliding wear characteristics of Zn-based alloys: Effects of partially substituting Cu by Si

In this investigation, the influence of partially replacing Cu by Si on the microstructure, the mechanical and the sliding wear properties of a Zn-based alloy has been studied. The presence of Si particles in the Si-containing alloy caused its room temperature tensile strength and elongation to be reduced compared with that not alloyed (with the element). However with increasing test temperatures, the difference in the strength values of the alloys decreased gradually; the trend reversed at the maximum test temperature. Elongation of the alloy comprising Si was less than the Si-free specimens over the entire range of test temperatures. Increasing the test temperature deteriorated the strength of the alloys while an opposite trend was observed in the case of their elongation. The alloys exhibited higher wear rates with pressure/speed, an exception being the wear behaviour of the Si-containing alloy wherein the wear rate decreased with speed beyond the sliding speed of 2.68 m/s. A similar behaviour. was also observed with the alloys in terms of the frictional heating. The study indicates that the (partial) replacement of Cu by Si improves the wear behaviour of the alloy system at high sliding speeds which was also reflected in terms of its superior thermal stability. The latter was indicated by a reduced influence of test temperature on the tensile strength of the Si-containing alloy when compared with that not comprising the element.