Thermodynamic optimization of the Mn–Ni system

The Mn–Ni system was critically assessed by means of the CALculation of the PHAse Diagram (CALPHAD) technique. The solution phases (liquid, body-centered cubic (δMn), face-centered cubic (γ(Mn, Ni)), complex body-centered cubic (αMn), and complex cubic (βMn)) were modeled with the Redlich–Kister equation. The intermetallic compounds αMnNi, βMnNi, MnNi2 and MnNi3, which have a homogeneity range, were treated as the formula (Mn, Va)(Mn, Ni), (Mn, Ni)(Mn, Ni), (Mn, Ni)Ni2 and (Mn, Ni)(Mn, Ni)3 by a two-sublattice model. In addition, the Mn–Ni phase diagram at high pressure 40, 80, and 100 kbar and the pressure-effect on transformation temperature diagram of the pure Mn were optimized, too. A set of self-consistent thermodynamic parameters describing the Gibbs energy of each individual phase as a function of composition, temperature, and pressure in the Mn–Ni system was obtained.