Effect of WC nanoparticles content on the microstructure, hardness and tribological properties of Al-WC nanocomposites produced by flake powder metallurgy

Abstract

Al-WC nanocomposites containing 0.1, 0.25, 0.4 and 0.6 v% of WC nanoparticles prepared by flake powder metallurgy route utilizing either cold pressing and sintering (CP–S) or hot-pressing (HP) to achieve optimum densification and hardness. The fabricated nanocomposites characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM) and optical microscopy (OM). The wear rate and friction coefficient of the HP samples quantified via a pin on disk wear testing machine. The results revealed that HP samples exhibited lower porosity and higher hardness values as compared with their CP-S counterparts. Adding WC nanoparticles up to 0.4 vol% resulted in the minimum porosity and maximum hardness. Nano-WC particles addition improved wear resistance and frictional behavior of the nanocomposite and the sample containing 0.1 vol% WC exhibited superior tribological properties. SEM micrographs revealed that the wear mechanism changed from adhesive to mainly abrasive with increased content of hard nano-particles.