New experimental phase equilibria information about the Fe-Cr-V-C system are presented and used to modify the thermodynamic description of the system. The main interest was focused on the composition of the MC and M 7 C 3 carbides and the necessary adjustment of the Cr and V distribution between carbides and matrix. A new set of thermodynamic parameter values describing the Gibbs energy of different phases was obtained. A number of calculated sections of the Cr-C, Cr-V-C, Fe-Cr-C, and the Fe-Cr-V-C systems are presented and compared against both new and old experimental information. Calculations on commercial alloys to verify the improvements in multicomponent systems are also presented. The present calculation using the Thermo-Calc software shows much better agreement with the new experimental results than previous assessments.

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A new thermodynamic database has been combined with an existing kinetic database to perform coarsening simulations in ternary systems including MC and M7C3 carbides in an fcc matrix. The kinetic database was revised taking into consideration the new experimental information on the Fe–Cr–V–C system obtained in the present work, and available experiments on the ternary Fe–Cr–C and Fe–V–C systems. After revision the agreement between experimental results and simulations was satisfactory. It was found that the interfacial energy of M7C3 was twice as large as that of the MC carbide. The calculations for commercial steels with 6 alloy elements gave results in satisfactory agreement with new experimental measurements. The present coarsening simulations use the calculated equilibrium state and the observed particle sizes as the state for the start of the simulations. All the simulations were performed with the DICTRA software.

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