Tribological behavior of WC–Ni cemented carbide irradiated by high-intensity pulsed ion beam

The tribological behavior of WC–Ni cemented carbide irradiated by high-intensity pulsed ion beam (HIPIB) at ion current densities of 100, 200 and 300 A/cm2 with 10 shots was studied under dry sliding tests against GCr15 bearing steel on a block-on-ring tribometer with 98 N and 0.47 m/s in order to explore the effect of HIPIB irradiation on the tribological property of WC–Ni cemented carbide. The cross-sectional microstructure, phase composition and microhardness of the irradiated WC–Ni samples were investigated by using scanning electron microscope (SEM), X-ray diffractometer (XRD) and Vickers testers. It was found that HIPIB irradiation led to significant surface hardening down to a hundred micrometers on the WC–Ni samples, and the reduction in specific wear rate and friction coefficient. The specific wear rate of irradiated samples decreased with increasing ion current densities. The original WC–Ni samples predominantly underwent an abrasive wear process accompanied with notable fragmentation and pullout of WC grains. The wear process of irradiated samples involved micro-abrasion and local adhesion in the initial stage, followed by a steady and mild abrasive wear. The preferential removal of Ni binder and pullout of WC grains is greatly suppressed for the irradiated samples due to combined enhancements in the carbide-binder bonding and binder phase strengthening by the HIPIB irradiation.