Thermodynamic modelling of the M6C carbide in cemented carbides and high-speed steel

Newly published experimental information on phase equilibria in cemented carbides and high-speed steel has shown that the solubility of Co, Nb, Si, Ta and V in the M6C carbide is higher than predicted by thermodynamic calculations. To account for this new information the model for M6C was extended. A thermodynamic description of the M6C carbide in cemented carbides and high-speed steels is presented. Several experimental studies have shown that there is a solubility of Si in M6C in high-speed steels, and the new model describes this solubility. A significant solubility of Co and Nb has also been observed, and was accounted for. The solubility of Nb, Ta and V in M6C in cemented carbide systems is described. The models are discussed, and the calculated equilibria are compared with the new experimental information.