Hybrid reinforcement of metal matrix composites (MMCs), particularly those based on aluminum, is widely recognized for resulting in excellent mechanical properties, such as high strength-to-weight ratio, enhanced wear resistance, and superior thermal conductivity. In this study, multi-wall carbon nanotubes (MWCNTs) and alumina (Al₂O₃) were used as the reinforcement for aluminum A356 via electromagnetic stirring (EMS). The composite was fabricated by varying the Al₂O₃ and MWCNT contents. Molten MMCs were then poured into the mold, and samples were collected after solidification. The effect of hybrid reinforcement by EMS on the distribution of microstructure and mechanical properties was investigated. Optical microscopy (OM) revealed that the presence of Al₂O₃-MWCNTs as reinforcement refined the grains, evolving from dendritic to rosette. The grains became closely packed, and reduced porosity was observed. The intermetallic phases in the composite were identified using secondary electron imaging–field emission scanning electron microscope (SEI–FESEM) and X-ray diffraction (XRD). Mechanical properties of the matrix were measured using a universal testing machine and a Vickers hardness test. The results indicate that the reinforcement percentage and stirring time significantly impact mechanical properties. The best properties were obtained with 0.5 wt% MWCNT, 6 wt% Al₂O₃, and 10 min of stirring. Under these conditions, the highest values for yield strength (94 MPa), tensile strength (221 MPa), elongation at break (11.37%), and hardness (89 HV) were achieved. These findings show that an optimum amount of reinforcement content and stirring time greatly influence the mechanical properties of the composite. The results show that the EMS effectively overcomes common challenges associated with hybrid metal matrix composites, namely proper particle distribution, reduced porosity, and enhanced mechanical properties. EMS provides a practical solution for producing high-performance aluminum composites suitable for structural and thermal applications with lower costs.

This study investigated the microstructure, hardness, tensile and tribological behaviour of a cooling slope Al–Si–Mg alloy following ECAP and T6 heat treatment. The optical and scanning electron microscopes were applied to investigate the microstructure of the as-cast material and heat-treated ECAPed Al–Si–Mg alloy. The dry sliding wear test was tested with three different loads of 10 N, 50 N, and 100 N with constant sliding speed and sliding distance at 1.0 m/s and 9000 m, respectively, using the pin-on-disc tribometer. The hardness and tensile properties were evaluated through microhardness, UTS, and YS measurement for the as-cast Al–Si–Mg alloy, both heat-treated with and without ECAPed alloys. Moreover, wear rate and COF in the Al–Si–Mg alloy with different loads were analysed and linked with microstructural and strength behaviour after the ECAP process. Meanwhile, these analyses of results were correlated with the behaviour of the as-cast Al–Si–Mg aluminium alloy and heat-treated non-ECAPed alloy. Results demonstrated that a combination of ECAP processing and T6 heat treatment improves the mechanical behaviour, while the COF and wear rate are improved at a load of 100 N.