Thermodynamic Assessment of High Entropy (Fe-Mn) Binary Alloy System Using Calphad Method

The thermodynamic analysis and calculations of the high entropy metastable binary alloy iron-manganese system have been carried out using the CALPHAD (Calculation of Phase Diagram) method THERMO-CALC (thermodynamic calculations) package and FEDATE database. The thermodynamic analysis contains the assessment and estimate of the phase diagram, Gibbs energy of mixing, excess Gibbs energies, thermodynamic molar activities, coefficient of activities, partial and integral values of Enthalpy for Fe-Mn alloy system at three elevated temperatures 1200K, 1225K, and 1250K. The entropy of the said alloy system is calculated by showing linear accordance with temperature. The sudden increase is found in the enthalpy curve due to the overlapping of grain boundaries of the system. The Enthalpy offers to increase the alloy system's heat contents with a rising temperature range. The alloy shows a positive deviation from Vegard's law, Henry's law, and the corresponding negative deviation from Raoult's ideal Gibbs curve. The obtained results show that the ferromagnetic states of Fe-Mn alloy are the most stable state FCC_Al#1. For Mn and Fe system, the phase equilibria show activity curve data for the solid-state and show ideal characteristics behaviors. A small positive deviation from Henry's law was observed from the perfect curve. The alloy offers equilibrium and good stability.