OpenCalphad is an open-source code for performing thermodynamic calculations using the Calphad approach. The code implements several different thermodynamic models which allow the description of thermodynamic state functions, such as the Gibbs energy, as a function of temperature, pressure and composition. By minimizing the Gibbs (or Helmholtz) energy, the equilibrium state can be determined for multicomponent systems under several different conditions in a so-called “equilibrium calculation“. In subsequent steps, other thermophysical properties and phase diagrams can be computed.

In the present version, the code can read thermodynamic databases using the most popular “tdb” format. The software can perform equilibrium calculations for multicomponent systems and show several thermodynamic properties under different conditions. The Compound Energy Formalism and other models have presently been implemented and new models will be added in the future. Other functionalities included in the last version of the code are step calculation and phase diagram calculation.