Fabrication and mechanical characterization of Al7075-T6/SiC/Gr/S-glass fiber particulate reinforced hybrid metal matrix composite using vacuum sealed stir casting technique

Abstract

Aluminum alloy-based metal matrix composites (AMMCs) are the most common material used in the field of automotive sectors because of their lightweight, economical, high strength-to-weight ratio, anti-corrosive properties, and large-scale availability. In the present study, Al7075-T6 as a base matrix with silicon carbide (1.5, 2.5, and 3.5 wt.%), graphite (2, 3, and 4 wt.%), and S-glass fiber (3, 4, and 5wt.%) as three distinct reinforcements was used for the fabrication of aluminum-based hybrid metal matrix composites through vacuum sealed stir casting technique. Taguchi design of experiments L9 orthogonal array and analysis of variance (ANOVA) have been adopted to investigate the influence of selected input process parameters such as silicon carbide (SiC), graphite (Gr), and S-glass fiber content on the output response parameters such as micro-hardness and impact strength. The experimental study revealed that micro-hardness and impact strength of synthesized composite have been enhanced by an amount of 31.40% and 33.33%, respectively, as compared with monolithic Al7075-T6 base alloy. In addition, the microstructure of fabricated hybrid AMMCs based on optical micrographs, SEM-EDS measurement along with XRD examination (for phase identification) showed a uniform dispersion of reinforcement particles over a base matrix. Furthermore, a fit regression model was prepared to develop the relationship between the variable process parameters corresponding to the response outcomes in terms of micro-hardness and impact strength.