This study presents a new concept of refining and enhancing the properties of cast aluminum alloys by adding nanoparticles. In this work, the effect of adding alumina (Al2O3), titanium dioxide (TiO2) and zirconia (ZrO2) nano-particles (40 nm) to the aluminum cast alloy A356 as a base metal matrix was investigated. Alumina, titanium dioxide and zirconia nano-powders were stirred in the A356 matrix with different fraction ratios ranging from (0%-5%) by weight at variable stirring speeds ranging from (270, 800, 1500, 2150 rpm) in both the semisolid (600 °C) and liquid (700 °C) state using a constant stirring time of one minute. The cast microstructure exhibited change of grains from dendritic to spherical shape with increasing stirring speed. The fracture surface showed the presence of nanoparticles at the interdendritic spacing of the fracture surface and was confirmed with EDX analysis of these particles. The results of the study showed that the mechanical properties (strength, elongation and hardness) for the nanoreinforced castings using Al2O3, TiO2 and ZrO2 were enhanced for the castings made in the semi-solid state (600 °C) with 2 weight% Al2O3 and 3 weight% TiO2 or ZrO2 at 1500 rpm stirring speed.

The present investigation studies the processing of A356 Al-Si alloy containing up to 5% vol.-% nano-sized al2o3 particles having size less than 500 nm. Composites were prepared using semi-solid casting route. To evaluate the results the alloys were further characterised by various metallurgical and mechanical characterization methods. The results showed that introducing nano-particles into semi-solid slurries promises to be a successful route for producing a new generation of cast metal matrix nano-composites (MMNCs). The nano-composites showed high strength values associated with superior ductility, low porosity content, high corrosion resistance, and improved electrical conductivity compared to the alloy without particles addition under the same casting conditions.

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The present investigation studies the prospects of using nanoparticles as reinforcement agents to gain improved performance of A356 Al cast alloy by adding up to 5% Al2O3 and TiO2 particles. The particles size was intentionally reduced from 10 μm to 500 nm to 40 nm. To evaluate the results, the alloys were further characterised by various metallurgical and mechanical characterisation methods. The results showed that introducing nanoparticles into semisolid slurries has a beneficial effect on optimising strength–ductility relationship in Al–Si cast alloys. The new material showed higher strength values with improved ductility compared to the monolithic alloy under the same casting conditions. Those particles were incorporated and entrapped within the interdendritic and/or grain boundary interface, as well as within the grains, developed during solidification.

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This paper investigates the mechanical and physical properties of Cu-Ni alloy (at 50-50 wt. %), mixed with different reinforcement materials such as carbon nanotubes CNT (0.5–2 wt. %) as nano particles, Al2O3 (1–4 wt. %) and SiC (1–4 wt. %) as microparticles. The obtained composite specimens characteristics were evaluated such as microstructure, density, electrical conductivity, thermal conductivity, hardness, and compression properties to determine the suitable reinforcement percentage that has the best physical and mechanical properties. The micron-sized Al2O3 and SiC and nano-sized CNT were added to enhance the mechanical and physical properties of the composite. The hardness and compression yield stress of Cu-Ni base composites have shown the most positive enhancement values of up to 135 % and 136 % of the matrix, respectively.

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