Studies on Aluminum–Fly-Ash Composite Produced by Impeller Mixing

Abstract

Metal matrix composites (MMCs) constitute an important class of design and weight-efficient structural materials that are encouraging every sphere of engineering applications. There has been an increasing interest in composites containing low density and low cost reinforcements. Among various discontinuously dispersed solids used, fly ash is one of the most inexpensive and low density reinforcement available in large quantities as solid waste by-product during combustion of coal in thermal power plants. Hence, composites with fly ash as reinforcement are likely to overcome the cost barrier for wide spread applications in automotive and small engine applications. To produce Al matrix cast particle composites, wettaility of the ceramic particles by liquid Al is essential. To improve wettabilty, elements such as Mg and Si are added into Al melt to incorporate the ceramic particles. The present investigation has been focused on the utilization abundant available industrial waste fly ash in useful manner by dispersing it into aluminium/aluminium-magnesium/aluminium-silicon matrix to produced composites by liquid metallurgy route. Wide size range (0.1-100μm) fly ash particles were used. These composites were observed with the help of optical micrography, x ray micro analysis, x ray diffraction, wet chemical analysis, and image analysis. The dry sliding wear behavior of the composites in the cast conditions was studied at different loads and different sliding velocities with the help of Pin-On-Disc wear test machine. The worn surfaces and wear debris were analyzed using optical microscope and scanning electron microscope. The mechanical properties such as hardness and tensile strength have been investigated.