Study on Composition of Rice Husk Silica Reinforcement to Hardness and Microstructure of Recycling Milled AA7075

Metal matrix composites based on aluminium reinforced natural waste are a well-known material industry application because they can reduce environmental pollution. This paper presents the hardness and microstructure analysis of recycling milled aluminium (AA7075) at various composition of rice husk silica. Recycling milled AA7075 reinforced with rice husk burned at 1000°C at various composition i.e., 2.5, 5, 7.5, 10 and 12.5 wt.%, were investigated. Metal matrix composites samples were prepared by cold compaction method due to the lower energies consumption and operating cost compared to conventional recycling by casting. The results reveals that the hardness of metal matrix composites samples increased at increasing of rice husk silica up to 5 wt.%. The addition of rice husk silica increased the irregularities of pore shape and it resulted in higher porosity and random pore shapes compared to unreinforced metal matrix composites samples. Based on investigation of metal matrix composites samples, rice husk silica has good potential to improve the material behavior with appropriate composition of rice husk silica to metal matrix composite.