Microstructure, Mechanical and Tribological Properties of the Multilayer Graphene Reinforced Wc-10ni3al Prepared by Microwave Sintering

Abstract

The multilayer graphene(MLG) reinforced WC-10Ni3Al cemented carbide was prepared by microwave sintering. The effects of sintering temperature and MLG content on the microstructure and mechanical properties of the WC-10Ni3Al cemented carbide were investigated. The promotion effect and strengthening mechanism of MLG on  WC-10Ni3Al by microwave sintering were analyzed. The tribological properties of WC-10Ni3Al-MLG and Ti6Al4V were studied, and the wear mechanism of WC-10Ni3Al-MLG was analyzed. The experiment result show that, when the sintering temperature was 1450 °C and MLG content was 0.5wt.%, the sample reached the highest mechanical properties and had a relative density of 96.9%, hardness of 1430 HV, flexural strength of 1410 MPa and fracture toughness of 15.7 MPa·mm1/2, which were 4.2%, 12.2%, 24.4% and 29.6% higher than those of the sample without MLG, respectively. The strengthening mechanisms of MLG in microwave sintered WC-Ni3Al consist of densification enhancement, fine crystal strengthening, energy absorption through MLG pulling out and breaking. The results of friction experiment show that the friction coefficient and wear rate of WC-10Ni3Al-MLG are lower than those of YG8. The lowest friction coefficient of 0.35 and the lowest wear rate of 1.69×10-5mm3N-1m-1 were obtained for WC-10Ni3Al-0.5wt. %MLG samples. A stable solid lubrication film was produced on the friction surface of the WC-10Ni3Al-MLG sample, which was conducive to reducing the breakage and wear of WC grains. MLG can enhance the stability of solid lubrication film and reduce its friction coefficient.

Keywords: MLG, WC, Ni3Al；Microstructure；Mechanical properties, tribological properties