Magnetic phase diagram of the Fe–Ni system

Magnetic phase diagrams of body-centered cubic and face-centered cubic Fe–Ni alloys were constructed using available experimental data and ab initio calculations. The results show that significant improvements in the “standard” diagrams (handbooks and CALPHAD databases) are required. The present work demonstrates that the CALPHAD magnetic model is not sophisticated enough to describe the Fe–Ni system. In addition, a new thermodynamic description of the lattice stability for pure Ni is urgently needed, since the recommended magnetic properties for CALPHAD modeling are distinct from the experimental and ab initio results. This work indicates that the construction of magnetic phase diagrams is indispensable during the phase transformation study of magnetic systems.