Aluminum is one of the most widely used materials in various industries, especially automotive and aerospace. However, in its pure form, this material has shortcomings such as low tensile strength and poor abrasion resistance and, therefore, has limitations in use. On the other hand, conventional forming and manufacturing methods such as powder metallurgy, extrusion and forging are generally unable to manufacture parts with complex geometry due to the processes characteristics and even, if possible, they require a long time and high cost. The present study focuses on the preparation of aluminum/silica nanocomposite using selective laser melting process which is one of the emerging manufacturing methods and does not have many limitations of the conventional methods. To this end, by designing various experiments and optimizing the process parameters, pure aluminum parts were manufactured by selective laser melting method with a relative density of 99.96%. A laser scan speed of 300 mm/s, laser power of 280 Watts, and hatch spacing of 0.08 mm was used to achieve this high density. Then, by adding one weight percent nanosilica reinforcement to aluminum, in the above-mentioned processing condition, a part was made of aluminum/silica nanocomposite with a relative density of 99.64%. The compressive strength and microhardness were improved by 20 and 18%, respectively, compared to the pure sample. The ball milling and direct mixing methods were studied to prepare the composite powder for manufacturing by the selective laser melting method. The direct mixing method was selected to maintain the spherical shape of the particles, which is necessary for selective laser melting. A laser scan speed of 200 mm/s, laser power of 280 Watts and hatch space of 0.08 mm were found as the optimum parameters in preparing the nanocomposite. Also, the results showed that the island scan patter led to higher density parts compared to the raster pattern. Keywords: Selective Laser Melting, 3D Metal Printing, Metal Matrix Nanocomposite, Aluminum, Nanosilica
