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Abstract

The study is to be undertaken to investigate the effect of Alumina particle size, sintering temperature, sintering time on the microstructure and mechanical properties of Al-Si7-Mg0.3 (A356). This metal matrix composite has been investigate by powder metallurgy. Powder metallurgy (PM) is a widely used fabrication method for producing metal matrix composites. This usually involves three major stages: blending of the metal and ceramic powders, pressing or cold compaction, and sintering. These last two steps are often combined during hot pressing. One of the advantages of PM compared to casting is having better control on the microstructure, where better distribution of the reinforcement is possible in PM compacts. Particle size and the amount of reinforcement had pronounced effect on the mechanical properties of composites. Proper addition of reinforcements to aluminum composites have a positive effect on mechanical properties, such as hardness, strength and wears resistance. The difference composition of Nano sized alumina particles is added 2wt%, 3wt%. The average size of aluminum and reinforcement particle size 30µm and 100nm respectively. For Proper production of the powder which will be placed in planetary ball mill. The sintering Temperature and time are in the range of 550-610ºc for 60-120 min. Forging had been involved for increasing the properties of composites at 350-400 ºc. The results that exhibited at elevated sintering temperatures, lower porosity is obtained. Higher relative densities are achieved at higher sintering temperature. Higher hardness was observed in samples containing finer alumina particles. The dependence of the diffusion to time may be explained for sintering temperature. It can be seen that the atomic displacement is proportional to the square root of time. This is responsible for the atomic diffusion leading to grain coarsening. It is seen that, at higher sintering temperatures, a denser structure is formed due to higher diffusion rates.