In the present work, A356 aluminum alloy matrix composites reinforced with 1.5, 2.5, and 5 vol.% MgO nanoparticles have been fabricated at various casting temperatures, viz. 800, 850 and 950 degrees C via stir casting method. Density, crystal structure and microstructure of the samples were investigated, in order to achieve optimum amount of casting temperature and MgO content. Also, the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicated that with increasing the content of the second phase (MgO), the amount of agglomeration and porosity increases. However, the microstructural characterization of the composite samples showed uniform distribution of reinforcement and presence of the minimal porosity. Density results showed adjacent values in comparison with theoretical ones. Composite cast at 850 degrees C, could be considered as the optimum fabrication conditions.

Keywords: Aluminum matrix composite; Stir casting; MgO Nanoparticles; Microstructure; Density