Microstructure and X-Ray Diffraction Analysis of Aluminum-Fly Ash Composites Produced by Compocasting Method

Abstract

Abstract Industrial and agro-wastes, such as fly ash, red mud, and rice husk ash, have become tremendous materials to be used as reinforcement in composite materials. In addition, these materials have potential to replace conventional ceramic reinforcement materials, such as aluminum oxide (Al2O3) and silicon carbide (SiC), as they can produce better composite materials with excellent properties and reduce the cost of production. Among the various types of waste materials used, fly ash has gained the widespread attention of researchers in aluminum matrix composite (AMC) production as reinforcement to enhance the properties of AMCs and reduce the production cost. In this research, LM6 (aluminum-silicon) alloy was reinforced with different amounts (4, 5, and 6 wt. %) of fly ash. These various compositions of LM6 reinforced with fly ash composites (AMCs) were fabricated by a compocasting method. The AMCs were then characterized based on microstructural (morphology, shape and size of the structure, and structure of existing elements) and phase analysis by scanning electron microscopy (SEM) and X-ray diffraction pattern (XRD). The existence of fly ash particles and some intermetallic compounds, such as Al2O3, silicon oxide, aluminum silicate, aluminum silicon, and calcium silicide, in the fabricated AMCs were confirmed through an XRD pattern. The SEM micrograph revealed that the microstructure of fabricated AMCs was refined with the incorporation of fly ash particles. The size of silicon phases decreased from 50 (unreinforced LM6) to 2.12 μm (LM6 fly ash composite with 6 wt. % of fly ash). Hence, it is found that the incorporation of fly ash particles is able to enhance the microstructure of fabricated AMCs.