Combined ab-initio and experimental assessment of A1-xBxC mixed carbides

The excess energies for A(1-x)B(x)C mixed carbides (where A and Bare metals) have been calculated using ab-initio calculations, for 14 systems. A thorough comparison has been made with experimentally assessed excess energies. The comparison shows that conventional ab-initio calculations applied to rather simple structural models can be used to predict the sign, magnitude and symmetry of the excess energy for A(1-x)B(x)C mixed carbides. The calculated excess energies have also successfully been used to describe several AC-BC systems where the experimental information does not give a unique determination of the excess energy in traditional CALPHAD modelling. The systems that have been studied are CrC-TiC, HfC-NbC, HfC-TaC, HfC-TiC, HfC-VC, NbC-TaC, NbC-VC, NbC-ZrC, TaC-VC, TaC-ZrC, TiC-VC, TiC-ZrC and VC-ZrC. (C) 2008 Elsevier Ltd. All rights reserved.