Effect of heat treatment on mechanical and tribological properties of aluminum metal matrix composites

Abstract

LM25 aluminum alloy reinforced with 10 wt% of TiB2, WC, and ZrO2 were squeeze cast to investigate the effect of T6 heat treatment on tribo-mechanical properties. Among all, WC-reinforced composite achieved superior mechanical properties at the aging time of 8 h. Microstructural examination performed on all composites and alloy concluded that the presence of WC in T6 LM25 caused reduction of α-Al dendrite size, exhibiting superior properties for this composite. X-ray diffraction analysis conducted on alloy and WC-reinforced superior composite revealed formations of phases, which improved their mechanical properties. Energy-dispersive X-ray spectroscopy analysis quantified the actual intensity of WC presence in the superior composite along with its other constituents. Response surface methodology model developed for wear test of the superior composite involves parametric range like applied load (10–50 N), sliding velocity (1–4 m/s), and sliding distance (500–2500 m). Analysis of variance along with regression analysis proved that, statistical analytical model developed good relationship between the actual wear rate and process parameters. Response surface plots represented the linearly increasing wear trend with respect to load and sliding distance. Wear rate dropped initially and raised later on along with velocity. Scanning electron microscopy exhibited the surface deformation prevailing on the composite surface at high load.