Study of hardness and wear behavior of surface modified AA 7075 with tungsten carbide using GTA as a heat source

Abstract

The aim of this work is to evaluate the role of tungsten carbide (WC) in increasing the hardness and improving the wear resistance of AA 7075 alloy. WC is reinforced into the surface of AA 7075 by using gas tungsten arc (GTA) as a heat source. Some of the GTA process parameters are maintained as constant, viz, contact-to-work distance and electrode tip angle, whereas the heat source current and the work speed are varied. With reference to the proper fusion of base metal, optimum GTA heat source parameter is finalized based on a number of trials. It is found that the hardness is reduced after the application of heat. To improve the properties, the alloy is subjected to heat treatment which included solution treatment, water quenching, and artificial aging. The hardness and wear behavior of the WC reinforced surface composite resulted in a positive trend. A comprehensive study on the microstructure of AA 7075 at different stages of the work is done using optical microscopy (OM), scanning electron microscopy (SEM), EDX analysis and X-ray diffraction (XRD).