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.