A thermodynamic description for the Co–Cr–Fe–Mn–Ni system

Based on the representative Co–Cr–Fe–Mn–Ni HEAs, many studies have been conducted to develop new HEAs with improved strength. The new HEA design can be efficient when utilizing computational thermodynamic prediction of phase equilibria because the phase distribution of alloys directly affects mechanical properties. Phase equilibria in HEAs can be effectively predicted by the CALPHAD (CALculation of PHAse Diagram) type thermodynamic calculation techniques, but the prediction of phase equilibria even for the well-known Co–Cr–Fe–Mn–Ni HEA system is still challenging due to the incompleteness of the thermodynamic descriptions for the constituent ternary systems. The purpose of the present work was to develop a self-consistent thermodynamic description for the quinary system by completing thermodynamic descriptions for all the constituent ternary sub-systems, newly carrying out thermodynamic assessments for the Co–Cr–Mn and Cr–Mn–Ni ternary systems. The reliability of the developed Co–Cr–Fe–Mn–Ni quinary thermodynamic description was confirmed by comparing calculated vertical sections of the quinary phase diagram with available experimental information. Graphical abstract