Thermal conductivity of WC-Co-TiC cemented carbides: Measurement and modeling

In the present work, the thermal conductivities of two WC-Co-TiC cemented carbides, YT5 (85WC-5TiC-10Co, in wt%) and YT15 (79WC-15TiC-6Co), are measured from room temperature to 1000 °C, and a physical model utilizing temperature, particle sizes, and phase fractions to describe the thermal conductivity of the WC-Co-TiC three-phase system is developed. Good agreements are achieved between the measured and predicted data. The results show that the thermal conductivity of YT5 decreases from 83.69 W/(m.K) to 62.25 W/(m.K) while that of YT15 increases from 37.78 W/(m.K) to 41.44 W/(m.K) from room temperature to 1000 °C. The difference between the thermal conductivities of YT5 and YT15 is attributed to their different phase fractions and interfacial thermal resistance of Co/(Ti,W)C. Furthermore, their different variation tendencies against temperature between YT5 and YT15 are explained by the variation tendencies of the phases and interfacial thermal resistance of Co/(Ti,W)C. The present work investigates thermal conductivities for WC-Co-TiC three-phase cemented carbides and reveals its correlation to the composition, temperature, and microstructure for the first time, laying a solid foundation for improving the service life of cemented carbides and further investigating the thermal properties for multiphase cemented carbides.