Assessment of Microstructure and Investigation Into the Mechanical Characteristics and Machinability of A356 Aluminum Hybrid Composite Reinforced with SiCp and MWCNTs Fabricated Through Rotary Centrifugal and Squeeze Casting Processes

The study explores the development of novel composites using nano-based hybrid reinforcements to enhance mechanical and wear properties. Specifically, A356 aluminum matrix composites containing a combination of silicon carbide particles (SiCp) and multi-walled carbon nanotubes (MWCNTs) were prepared using the Rotary and Squeeze casting methods. The research aimed to investigate the mechanical properties and microstructure of A356 alloy with varying percentages (5%, 10%, and 15%) of SiC-MWCNT hybrid reinforcements added at a 2:1 ratio. The results indicated that the squeeze casting method led to refined silicon and intermetallic compounds in the microstructure, and the dispersion of SiCp in the A356 alloy was homogeneous. Grain refinement was achieved, with a notable 35.22% improvement compared to the A356 alloy without reinforcements. The addition of SiCp, intermetallics, and Si particles increased tensile and yield strength. The study also observed a reduction in Si phase and alpha-Al grains with increased squeeze cast parameters. Furthermore, the aspect ratio and mean diameter of Si needles decreased by 31% and 43%, respectively, compared to the base alloy. After the squeeze casting process, improvements in yield strength (17.99%), tensile strength (36.66%), and percentage of elongation (195.91%) were noted compared to the composite prepared by rotary centrifugal casting methods. Lastly, the study evaluated the machinability of the hybrid MMC through an optimization technique, Entropy-PROMETHEE (Entp-PRMT). Overall, the research demonstrates the potential of nano-based hybrid reinforcements and the squeeze casting method to enhance the mechanical properties and microstructure of A356 aluminum matrix composites, offering promising applications in various industries.