Comparative study on the mechanical, tribological, morphological and structural properties of vortex casting processed, Al-SiC-Cr hybrid metal matrix composites for high strength wear-resistant applications: fabrication and characterizations

The cast aluminum-silicon alloys are used to make various automobile components like pistons, cylinder blocks, piston insert rings, connecting rod, brake disc, etc. but low strength, hardness, and wear resistance restricted their use in several applications. Silicon carbide reinforced aluminum matrix composites exhibit better properties than base metal alloys. As an alloying element, the chromium improves the hardness, strength, and elastic limit of the steel. In this study, the characterization of Al-Si alloy-based metal matrix composites that are reinforced with silicon carbide and chromium is performed with the help of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), microhardness test, tensile test, sliding wear test, scratch test, and porosity analysis. The aluminum matrix composites with a varying weight percent of chromium (0-3 wt.% in steps of 1.5) and a fixed percentage of silicon carbide (10%) were formulated through the vortex casting process. The SEM and EDS images illustrate the occurrence and somewhat uniform dispersion of the reinforcement particulates. In hybrid composites, the Cr3C2 compound formation is observed with the least intensity. The reinforcement content contributes significantly to improve the hardness, strength, abrasion resistance, and wear resistance along with a modest reduction in the ductility and gain in friction coefficient. The porosity level obtained in the composites revealed that composites are free from casting defects.