Calculation of the Ti-C-N System

The thermodynamic properties of the Ti-C-N system is assessed using previous assessments of the Ti-C and Ti-N systems and experimental information on the ternary system. The liquid phase is described over the whole range of composition using a substitutional model and the fcc titanium carbo-nitride in the Ti-TiC-TiN triangle using a two-sublattice model (Ti) 1 (Va, C, N) 1 . A metastable miscibility gap occurs in the fcc phase and part of it appeared to be stable in previous assessments. Isothermal sections are calculated and compared with experimental information from 773 to 1923 K. The liquidus surfaces and the minimum pressure needed to prevent boiling of the liquid are calculated. The isoactivity lines in fcc for titanium, carbon and nitrogen are calculated at 1923 K.