Effect of Heat Treatment on Micro Hardness and Microstructural Properties of Al 6063 Alloy Reinforced with Silver Nanoparticles (AgNps)

Abstract

The demand for light weight metals in engineering design has led to the increasing use of aluminum and its alloys. However, conventional high-strength casting aluminum alloys usually exhibit low ductility and toughness, as a result of boundary segregation and coarse dendritic grains which result in its limited application in large-sized and complex shaped work pieces. Also, the possession of a significant low resistance to corrosion of Al 6063 alloys has been a major challenge in applications involving acidic and alkaline media. In this study, silver nano-particle was extracted from a fixer solution. Al 6063 was impregnated with silver Nano-particle at different percentage ratio to form a metal matrix nano composite and the Hardening heat treatment of the reinforced metal matrix nano composite was performed. The elemental composition of Al 6063 prepared from scrap was determined using Light Emission Polyvac Spectrometer. The hardness and microstructural analyses of the composites were evaluated. The micro hardness of the composites was positively influenced by the addition of AgNps and the hardening heat treatment process it was subjected to. The percentage increase in micro hardness of the sample not heat treated but impregnated with 3% and 9% weight nano particles are 20% and 22% respectively. Subjecting these samples to heat treatment further increased the micro hardness to 33% and 37% respectively. The morphology of the composites revealed reasonably homogenous distribution of the reinforcement in the matrix of Al 6063 alloy. It can be concluded that both percentage increase in weight fraction of AgNps and hardening has significantly increased the micro hardness and refined the grain morphology of the Al-AgNps composites.