Critical Evaluation and Optimization of the Fe-N, Mn-N and Fe-Mn-N Systems

Abstract

Thermodynamic optimization of the Fe-Mn-N system was performed using CALculation of PHADiagram method based on critical evaluation of all available phase diagrams and thermodynamic data. The Gibbs energies of liquid phase and solid solutions were described using the Modified Quasichemical Model and Compound Energy Formalism, respectively. The Gibbs energies of pure monoatomic N in both liquid and various solid states were newly reassessed for resolving the discrepancies left in the currently available database. Several existing problems in the previous assessments for the binary Fe-N and Mn-N systems were resolved and more precise and consistent description of the ternary Fe-Mn-N system was achieved with less number of model parameters, comparing to the previous assessment.