MECHANICAL AND TRIBOLOGICAL CHARACTERIZATION OF HYBRID Al6061/B4C/Gr COMPOSITES BY STIR CASTING TECHNIQUE

This research focuses on the fabrication of Al6061/B4C/Gr metal matrix composites as well as the mechanical and wear properties analysis. A liquid metallurgy stir casting process was used to cast the Al6061 alloy matrix composites with specific wt.% of B4C and constant wt.% of graphite. In this work, newly developed composites of Gr (particle grain size: 0-20 mu m) and B4C (particle grain size: 0-30 mu m) are reinforced with Al6061 pure alloy, which enhanced the mechanical and wear properties when compared to Al6061 pure alloy. Microstructure analysis was carried out concerning the developed mechanical properties. Furthermore, the dry sliding wear behavior of Al6061/B4C/Gr metal matrix composites was investigated at a sliding speed of 1m/s and a sliding distance of 1500mm against a hardened EN-31 disc under the corresponding load of 19.68N. The minimum wear rate is 1.15x10-2mm(3)/m found at 15wt.% B4C and 2wt.% graphite and the coefficient of friction is 0.54 that decreases with graphite addition, with the lowest value obtained with 5wt.% B4C and 2wt.% graphite. Al6061/10wt.% B4C/2wt.% Gr particles-reinforced composite material demonstrated the highest tensile and flexural strengths. The hardness,compressive and tensile strength of the Al6061/15wt.% B4C/2wt.% Gr particles-reinforced composite material were the highest. Scanning electron microscopy was used to examine the worn surfaces of wear specimens. The main objective of this work is to develop hybrid Al6061/B4C/Gr composites with improved mechanical and wear properties when compared with the base alloy. Al6061 is widely used in automobiles parts like engine block, piston rings, alloy wheels, marine industries, etc. B4C used in the composite improves strength and is used commonly in armed bullet proof. The Gr present in the composite improves wear resistance, and therefore applied in wear-resistant parts like brake, piston with cylinder, etc.