Effect of particle size of rice husk ash on aluminium/graphene composites

Abstract

Aluminium/graphene (Al/G) composite has gained wider engineering applications because of its unique properties such as lightweight, excellent corrosion resistant, improved strength and enhanced thermal conductivity. However, difficulty in dispersing graphene in molten aluminium remains one of the major optimization challenges. This study developed, by stir casting technique, composites of aluminium alloy from recycled aluminium can, 0.4 wt. % graphene (G) and 1.6 wt.% rice husk ash (RHA) with particle sizes of 150, 300 and 600 μm. The tensile, hardness, impact and fatigue properties were analyzed using Instron Extensometer, Vickers hardness tester, Charpy Impact machine and rotating fatigue machine respectively. Furthermore, the cast samples were characterized using scanning electron microscope (SEM) and X-ray diffractometer (XRD). The morphology of the microstructure of all composites showed the retention and uniform distribution of G and RHA particles in the Al matrix devoid of presence of harmful aluminium carbide with improved mechanical properties. The study established a new approach of dispersing graphene in molten aluminium through a stir cast method with 150 μm particle size of RHA given the best mechanical and morphological properties.