Mechanical and tribological performance of Al6082 composites reinforced with micro-sized SiC particles via stir casting

The present work deals with the development and evaluation of aluminium 6082-based composites reinforced with micro-sized silicon carbide (SiC) particulates produced through an ex-situ stir casting technique. The aim was to examine the influence of varying reinforcement proportions (0, 6, 8, and 10 wt.%) on the mechanical and tribological responses of the composites. The stir casting was carried out under carefully controlled parameters with fixed stirring speed, time, rotor eccentricity, and spray pressure to ensure uniform processing. SiC particles were gradually introduced into the molten aluminium and dispersed through continuous stirring. The produced composites were subjected to microstructural analysis, tensile strength testing, hardness evaluation, and dry sliding wear tests. Microstructural observations confirmed a uniform distribution of SiC particles with minimal agglomeration. The mechanical results showed that increasing the SiC content led to higher tensile and yield strength, along with improved hardness. The findings indicated that the ultimate tensile strength (UTS) of the composite increased gradually as the SiC content increased, from 139 MPa for the unreinforced alloy to 145, 204, and 210 MPa at 6, 8, and 10 wt.% of SiC, respectively. Consequently, the strain-to-failure ratio decreased from 0.048 mm/mm for the unreinforced alloy to 0.039 mm/mm, 0.035 mm/mm to 0.030 mm/mm, respectively. The composites containing 6, 8, and 10 wt.% of SiC had hardness values of 101, 116, and 132 HV, respectively, compared to the unreinforced Al6082 alloy’s 67 HV. These improvements are attributed to effective load transfer from the matrix to the reinforcement and grain structure refinement. The wear resistance also improved significantly in reinforced samples compared to the unreinforced alloy. While the base aluminium alloy exhibited adhesive wear, the composites demonstrated a shift to abrasive wear mechanisms, owing to the presence of hard ceramic particles. Additionally, smaller particle size and higher reinforcement content contributed to further enhancements in performance. The findings align with previously reported trends in similar composite systems and suggest that post-processing treatments may further improve fatigue resistance and structural integrity. This work contributes to understanding the role of reinforcement parameters on composite behaviour and confirms that Al6082 composites with SiC reinforcements are well-suited for applications such as brake drums, bearings, gears, and drive shafts where high strength and wear resistance are essential.