Effects of Al2O3 nanoparticles volume fractions on microstructural and mechanical characteristics of friction stir welded nanocomposites

Abstract The objective of the present study is to investigate the effect of Al2O3 nanoparticles volume percentage on tribological, mechanical and microstructural characteristics of 6061-T6 aluminum alloy based particulate-nanocomposite (P-NCs) fabricated using friction stir welding (FSW) process. Optical microscopy (OM) and scanning electron microscopy (SEM) was employed to evaluate the (a) microstructures of the produced nanocomposites to ascertain the distribution of Al2O3 nanoparticles in the nugget zone; (b) nanocomposite depth formed on Al-alloy matrix, and (c) fractured and wear characteristics. Results reveal that the produced P-NCs had a depth of 3286 µm across the perpendicular x-section of the weld nugget zone of P-NCs. With the increase in a volume percentage of Al2O3 nanoparticles there was a tremendous increment in the microhardness up to 125 HV which is higher than as-received AA6061-T6. It was also noticed that the tensile strength and the wear resistance of produced P-NCs were significantly increased at 0.3 vol% of Al2O3 nanoparticles as compared to 0.2 and 0.4 vol%. The corresponding mechanical and wear properties results were correlated to microstructure and fractography results. Graphical Abstract