Investigating the Effect of Particle Sizes of SiC and Graphite on Strengthening of Aluminium Metal Matrix Composites

The endeavour of this research work is to scrutinize the effect of the reinforcement materials silicon carbide (SiC) and graphite (Gr) on the mechanical properties of Al-Mg-Si alloy (AA-6061). Samples of the composites were fabricated using the stir casting technique, incorporating four weight (wt.) ratio of individual reinforcement and two different sizes of the particles. SiC, a resilient ceramic, and graphite were chosen as reinforcement to estimate their shared impact on the mechanical characteristics of the composite. Hybrid metal matrix composite (MMCs) were created with varying weight percentage of 4%, 3%, 2%, and 1% for the above selected reinforcements separately with two combinations of the particle dimensions: System-I (SiC-25 µm and Graphite- 75µm) and System-II (SiC-5 µm and Graphite- 25 µm). Mechanical characterization of composite samples including hardness, wear rate, compressive strength, was analyzed for both System-I and System-II. Scanning electron microscopy was employed for microstructure analysis, and X-ray diffraction was used for phase identifications. Mechanical characterization revealed both System-I & II with uniform dispersion of reinforcement particles. System-I exhibited higher density and lower wear resistance compared to System-II under all load conditions.