Physical Properties and Hardness of Treated Amorphous Silica as Reinforcement of AA7075 Recycled Aluminum Chip

Abstract

Solid state recycling techniques of waste aluminum materials without melting the material is a process that consumed less energy consumption. The reuses of waste materials such as aluminum scrap and rice husk ash lead to the friendly environmentally and low cost of production. Physical properties and hardness of treated amorphous silica as reinforcement of AA7075 recycled aluminum chip were investigated. Recycled aluminum sample AA7075 reinforced treated amorphous silica by rice husk ash was prepared by the technique of powder metallurgy (PM) owing of reduced energy consumption and operating cost in comparison with conventional cast-recycling. The presence of silica exists in rice husk ash obtained after through chemical treatment and burning process of rice husk at temperatures of 700°C for 2 hours. The effect of aluminum recycled chip with rice husk ash composite with composition of 2.5 wt.%, 5 wt.%, 7.5 wt.%, 10 wt.% and 12.5 wt.%, on physical properties and hardness were investigated. Based on investigation to AA7075 recycled aluminum chip reinforced treated amorphous silica by rice husk ash, the porosity and water absorption of composite of metal matrix is increase with increasing of composition of treated rice husk ash as the density shows decrease when the treated rice husk ash is added up to 5 wt.%. The addition of treated rice husk ash has improve the hardness of composite of metal matrix from 53.49 Hv of 100 wt.% of AA7075 recycled aluminum chip to 69.53 Hv of composite of metal matrix at 10 wt.% of composition of treated rice husk ash. Based on this research, treated amorphous silica as reinforcement has enhance the physical properties and hardness of recycled aluminum chip sample in composition up to 10 wt.% of treated amorphous silica.