Effect of the Dispersity of Cubic Phase on the Microstructure and Mechanical Properties of Ultra-Fine WC–10Co based Cemented Carbides

摘要

In order to control the grain growth and improve the high-temperature performance, some carbides such as, VC, Cr_3C_2, TaC and NbC, are usually added into the WC–Co cemented carbides. However, above the saturation solubility, the precipitated brittle honeycombed cubic solid solution leads to inhomogeneity of microstructure, and thus deteriorate the mechanical properties. In this work, the effect of the dispersity of cubic phase on the microstructure and mechanical properties in ultra-fine WC–10Co cemented carbides was investigated. Based on the thermodynamic calculation and experimental research (SEM, EPMA and EBSD), the main factors affecting the segregation of cubic phase could be revealed. An effective approach to control the segregation of cubic phase in the ultrafine WC–10Co based cemented carbides was thus developed. With the cubic phase segregation gradually eliminated, a dramatically improved combination of hardness and transverse rupture strength of WC–10Co materials was obtained.