Impact of tungsten on the surface of aluminium- silicon alloy on microstructure, hardness and wear rate using GTA

摘要

A study was carried out to determine the effect of tungsten addition on hardness, microstructure and wear behaviour of surface modified as-cast Al - Si alloy. The heat source utilized for modifying the surface of the substrate was Gas Tungsten Arc. Tungsten were deposited on the Al - Si alloy substrate using poly vinyl alcohol as binder and the SMP were performed. By using Lyzer Instruments optical microscope and HITACHI SU6600 FE-SEM microstructural analysis was carried out. The hardness and wear rate of the modified layer were calculated by using a micro-hardness tester and a pin-on-disc wear tester machine. The presence of elemental composition in the modified layer was determined by using Energy Dispersive Atomic X-ray Spectroscopy and its confirmation through XRD analysis. It was inferred from this study that a fine grain microstructure was observed in the modified layer. The hardness and wear resistance was found to increase as a result of W addition and also due to the formation of dispersion strengthening mechanism. The coefficient of friction was found to be independent of the hardness.