Thermal conductivity of cemented carbides

Hard-metals are powder metallurgical composites made from carbides or carbonitrides of refractories with minor amounts of a ductile binder phase. Their thermal conductivity is very important as concerns their behaviour under thermomechanical loading in use. For practicable and quick measurement, a stationary method and a non-stationary one were introduced. The experimental results show that the thermal conductivity of hard-metals varies over the wide range between 10 and 100 Wdeg−1m−1, mainly reflecting the nature of the hard phase and its defect structure. The dependences on the position of the refractory in the Periodic Table and on the stoichiometry are discussed. For hard-metals based on titanium carbide, the thermal conductivity is proportional to the electrical one, i.e. the Wiedemann-Franz law holds with a modified Lorentz factor.