Al6061 reinforced with the hard particles, have higher strength, stiffness and wear and creep resistance than their unreinforced alloys in a wide temperature range and can be used for automotive components and aircraft structures. In the present work, Al6061/nano-Al2O3 composites were fabricated by stir-casting process through injection of Al2O3 particles into the molten Al alloy by the argon gas along with stirring using a mechanical stirrer, followed by extrusion at 550°C. The effects of adding nanoparticles (Al2O3) and extrusion process on the microstructure properties of the composites were investigated. The results show that Al2O3 nanoparticles are reasonably distributed in the matrix alloy with low agglomeration and porosity. Al2O3 particulates were distributed in the inter grains, with some particulates locating in grains. Also nanoparticles effectively caused to decrease grain size of matrix.

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