Research on Microstructure and Mechanical Performance of NbC and TiC on WC-12Co

Abstract

Three cemented carbide samples, WC-12Co, WC-12Co-0.5NbC and WC-12Co-0.5NbC-0.5TiC were prepared by vacuum liquid phase sintering. Combining SEM (scanning electron microscope), XRD (X-ray diffraction), and mechanical property testing, the effects of different combinations of grain growth inhibitors on the properties and microstructure of cemented carbide were analyzed and studied. The results show that there are significant differences in the microstructure and mechanical properties of cemented carbide samples with the addition of NbC and TiC. Both NbC and TiC can effectively suppress the abnormal growth of WC grains in the alloy, resulting in a uniformly distributed and fine grained hard alloy. Further comparative analysis shows that adding appropriate amount of NbC can effectively improve the fracture toughness of the sample; adding an appropriate amount of NbC and TiC simultaneously can further improve the surface hardness and wear resistance of the sample. Compared to the alloy sample without any inhibitor, the Vickers hardness value of the sample with NbC and TiC added simultaneously reached 1952.4HV30, increasing by about 10%, and the wear loss decreased by about 30%, compared to the alloy with single addition of NbC, the wear loss of the sample with both NbC and TiC decreased by about 27.5%. In general, when NbC and TiC are added simultaneously, the comprehensive properties of the sample alloy are more excellent.