Tribological behavior of ZK60 magnesium matrix composite reinforced by hybrid MWCNTs/B4C prepared by stir casting method

Abstract

In this study, ZK60 alloy matrix composites reinforced by 10 wt% boron carbide (B4C) and various 0–1 wt% multi-walled carbon nanotubes (MWCNTs), and 0.5 wt% MWCNTs and different 5–20 wt% B4C contents were prepared via stir casting method. The wear behavior of the samples was assessed using the pin-on-disk configuration at room temperature under loads of 40 and 80 N, and the sliding speed of 0.5 m/s. The worn surface and tribo-layer generated were investigated using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses. The results demonstrated that at low loading the friction coefficients of samples containing MWCNTs were lower compared to those of the samples with different B4C contents. The wear rates were decreased by increasing the MWCNTs content up to 0.5 wt%, while they were increased by increasing the B4C content to higher levels. The worn surfaces of the samples showed that at 40 N, the abrasion and plastic deformation mechanisms were dominant, while delamination and oxidation wear were dominant at 80 N. All in all, the sample containing 10% B4C and 0.5% MWCNTs showed the highest wear resistance.