Wear response of a zinc-based alloy containing silicon as influenced by material microstructure and test conditions

Abstract

This paper describes observations pertaining to the sliding wear response of a zinc-based alloy comprising silicon. Wear tests were performed in oil lubricated condition over a range of applied pressures and sliding speeds. The influence of microstructural changes (brought about through heat treatment) on mechanical properties and wear characteristics of the samples has also been investigated. The study indicates that microstructural alterations brought about through heat treatment could be beneficial in terms of improved wear response of the zinc-based alloy despite a reduction in hardness and tensile strength. However, the extent of improvement depends on test conditions like sliding speed and pressure. Factors like hardness, strength, cracking tendency, thermal stability, morphology and mode of distribution of various microconstituents in the alloy microstructure were noted to be responsible for specific wear behaviour in different test conditions. Different slopes exhibited by the data plots could be explained in terms of changing mode of predominance of operating wear mechanisms. The observed wear behaviour of the alloy was substantiated further through the features of wear surfaces, subsurface regions and debris particles.