Study of Mechanical properties and erosion wear behaviour of novel Al-25Zn alloy/SiC/Graphite hybrid composites

Abstract

Abstract Plain bearings are extensively used in many engineering application. The erosion of bearing material is one of the major parameter that affects the performance of bearing. In this investigation, four Al-25Zn alloy samples added with silicon carbide and graphite particles were manufactured using stir casting technique. The mechanical properties, surface morphology and solid particle erosion wear characteristics of fabricated specimens were studied. Erosion wear characteristic of specimens was investigated using air jet erosion tester with silica sand particles of irregular shapes of size approximately 150 µm as an erodent at three impact velocities 20, 40 and 60m/s and three different impingement angles 15, 30 and 45 deg. for 25 minute as per Taguchi L9 orthogonal array. The eroded surfaces were characterized by using scanning electron microscope (SEM). The hardness, tensile strength and erosion resistance of Al-25Zn alloy is found to be increased with the addition of hard SiC particles. The reinforcement of graphite in Al-25Zn alloy enhances the erosion resistance, impact strength and tensile strength of composite, in spite of the substantial decrease of hardness. The analysis of variance indicates that the impact velocity is the most important parameter as compared to impingement angle for the erosion of the composites. The existence of hard SiC and soft graphite particles in matrix alloy reduces the erosion of composite due to deflection as well as indentation