Microstructures and mechanical properties of WC-Co-xCr-Mo cement carbides

In the present work, the effects of Mo/Cr addition on the microstructure and the resultant property of cemented carbides were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDS) and Vickers hardness test. The results show that addition of Mo/Cr elements contributed to a significant improvement of WC-Co cemented carbides hardness. The enhanced hardness is ascribed to the decreased grain size of WC with increasing Cr content. In addition, Cr element addition would promote the segregation of M7C3 phase surrounding the η-phase, which inhibits the growth of η-phase, and results in finer and more disperse η-phase. The evolution mechanism of η-phase and the segregation of M7C3 phase during sintering process were discussed systematically.