The Structure and Properties of Zinc-Aluminium Based Bearing Alloys

Abstract

A Series of zinc-aluminium based binary and ternary alloys which may be suitable for bearing purposes have been produced by casting. Their structures have been investigated by optical and electron microscopy and by X-ray diffraction, in the as-cast and heat-treated conditions. The ageing response of the alloys was monitored using hardness and quantitative X-ray diffraction techniques and the kinetics of the decomposition of the supersaturated a/a* and 8 phases were determined and related to the structural changes. This allowed the most suitable heat-treatments to be deduced. Some mechanical properties relevant to the application of these alloys as monolithic bushing materials have been determined, i.e. impact properties, creep and tensile properties at ambient and elevated temperatures. It was shown that the creep data may be correlated by a parametric method which allows the estimation of stress to a certain strain under different conditions. A comparison of the wear resistance of selected alloys with cast iron and phosphor bronze was carried out, and it was shown that certain of these alloys were comparable or superior to these.