Cr-Fe-Ni Sigma Phase Finite Temperature Calculations

The Cr-Fe-Ni system is of great technological importance and is a fundamental part of many key alloys.
The sigma phase, much like other topologically close-packed phases, is a brittle phase that is detrimental to the properties of the alloys in which it forms.
This work uses first-principles calculations based on density functional theory (DFT) to develop a description for the sigma phase using a 5 sublattice model
with magnetic configurations considered. A high-throughput DFT workflow for efficient, robust relaxation of structures and calculation of finite temperature
properties was written and implemented using the atomate software package. A CALPHAD model for the sigma phase was developed automatically using the ESPEI
software package. The energy of the electronic structure was then assessed to determine the stability. From this the interaction parameters will be determined
using ESPEI in order to work toward a more complete description of the Cr-Fe-Ni system.