Abrasive wear behavior of WC nanoparticle reinforced magnesium metal matrix composites

Abstract

In this study, abrasive wear characteristics of AZ31-WC nanocomposites with varying weight percentage of nanoparticles (0, 0.5, 1, 1.5 & 2) are examined. AZ31-WC nanocomposites have been fabricated by ultrasonic vibration assisted stir casting method. Optical microscopy and scanning electron microscopy are employed to perform characterizations of cast composites. Density and micro hardness of nanocomposites are also investigated. Effect of abrasive grit size and sliding distance on abrasive wear behavior and friction behavior of nanocomposites are evaluated using pin-on-disc tribotester. Worn surfaces are studied with the help of 3D optical surface plotter, SEM and EDAX to find dominant wear mechanism at several experimental conditions. Microscopic observations disclose that distribution of WC nanoparticles is uniform throughout the matrix. Density and micro hardness increase with increasing percentage of WC nanoparticles. Moreover, significant improvement in wear resistance and friction behavior is observed by incorporation of WC nanoparticles. Wear resistance of Mg-2WC nanocomposite is improved around 56% than base alloy when tested with 400 grit SiC paper and 50 mm track diameter. Higher grit size abrasive paper exhibits less wear in composites. 3D Surface plots of worn surfaces show that, surface roughness is decreased with increasing wt% of WC. Surface roughness of worn surface of Mg-2WC nanocomposite tested with 800 grit, 50 mm track diameter has 35.06% less surface roughness than Mg-2WC nanocomposite tested with 400 grit, 50 mm track diameter. Investigation of worn surfaces discloses dominant mechanisms as abrasion, adhesion and delamination at several experimental conditions.