Phase Equilibria in the System Tungsten—Carbon

Abstract

Quenching from high temperatures, supplemented by differential thermal analysis, has shown that the tungsten‐carbon binary is characterized by eutectic temperatures of 2710° and 2760°C between W and W 2 C, and between W 2 C and a new high‐temperature phase (β‐WC), respectively. Carbon solubility in excess of stoichiometric W 2 C is evident only at 2525°C, the eutectoid temperature between W 2 C and WC. W 2.35 C melts congruently at 2795°C. A new fee phase (β‐WC), stable only above 2525°, has been discovered between W 2 C and α‐WC. The cubic phase is formed by a periteci reaction at approximately 2785°C and has a broad homogeneity range ear the solidus. The phase, α‐WC, decomposes into β‐WC and C at 2755°C, approximately 25°C below the melting temperature.