Evaluation of Mechanical Properties of Locally Recycled Aluminium Alloy Scrap

Abstract

Recycling of aluminium alloy scraps reduce the amount of waste directed into landfills. It is a vital part of the aluminium smelting industries. However, some local aluminium smelting craftsmen/artisans in Nigeria cast their aluminium scraps without considering the mechanical properties of the casting obtained from aluminium scraps. This study investigated some of the mechanical properties of cast aluminium alloy namely; tensile strength, impact, and hardness, and the microstructure of the locally recycled aluminium alloy in Nigeria. A permanent mould casting process was adopted in the smelting of the scraped aluminium and their properties were examined. The metallographic specimen of the sample was grinded and polished in a Dia-Pro suspension solution (3μm) on an MD-DAC and DP-DAC 300mm polishing cloth while the surface was exposed to a Keller enchant of 15mil of hydrochloric acid, 10mil of water and 10mil of hydrofluoric acid before viewing under the microscope. From the result, the ultimate tensile strength, impact, and Brinell hardness were 54.87MN/m2, 6.1J and 64.33BHN, respectively. The metallographic result from the smelted sample revealed a coarse and rough surface microstructure.