EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

A phase diagram provides a wealth of information, such as coexistence lines, phase stability and phase changes along the thermodynamic variables. It is crucial that an interatomic potential is able to describe significant sections of the phase diagram reliably. The calculation of phase diagrams requires estimating the Helmholtz and Gibbs free energy of the different phases and its variation with the thermodynamic state variables. The calculation of free energies, however, is far from trivial. Although numerous methods exist, they are either technically challenging or computationally intensive. Here, we formalise automated workflows to calculate both Helmholtz and Gibbs free energies and provide corresponding computational tools. We further illustrate the calculation of the temperature dependence of thermodynamic potentials in an automated manner. Our automated workflows need minimal user input and are computationally efficient. In this way our method also provides a robust way to test and validate interatomic potentials through the calculation of phase diagrams. We illustrate the use of our workflow for calculating the pressure-temperature phase diagram for the recently developed Atomic Cluster Expansion potential for Cu and discuss extensions to multi-component materials.