Effects of Combined Addition of Cr₃C₂ and NbC on Microstructure and Properties of Cemented Carbides Prepared by WС-Co Composite Powder

With addition various contents of combined grain growth inhibitors Cr3C2 and NbC into the ultrafine WC-Co6% composite powder, and the effects of codoped Cr3C2 and NbC addition on microstructure and properties of the alloys have been investigated by X-ray diffraction, scanning electron microscopy. The results showed that increasing the content of inhibitors in the composite powder, the abnormal grain growth disappeared and homogeneous ultrafine grain structure formed, i.e., the grain growth inhibitor promoted sintering densification process. WC grains were refined by the comprehensive effects of the Cr3C2/NbC dissolving in the Co phase to alter the interface energy and interfere the WC solution in the binder phase, which prevents the structure of cobalt change from the face-center-cubic into dense-hexagonal crystal, and to increases the transverse rupture strength.