CalIPh (Calculation by Interval of Phase Diagrams) is a free software that uses interval arithmetic to compute certified phase diagrams (freed from any possible numerical errors) from analytic expressions of mixing enthalpies.

Current version computes only condensed-phases binary diagrams in the temperature-composition axes.


CalIPh is hosted as a webservice on a server provided by the University of Nantes and relies upon the infrastructures and software platforms of the LS2N lab. It employs IBEX in order to compute the diagrams and pycalphad parser for the input files in TDB format.

CalIPh follows a novel 4-steps approach in order to guarantee the computation of a phase diagram:

  1. critical points of the diagram are computed very precisely and certified (interval computations make it possible to assert the conditions of mathematical solution existence theorems);
  2. all the solubility limits of each phase, and the interactions between each pair of phases, are computed and certified as well;
  3. the solutions obtained in the previous two steps are combined in order to determine and connect the components of the phase diagram;
  4. the components with lowest energy are identified in order to compose the final diagram.

Contact : CalIPh-software@Zuniv-Nantes.Zfr (remove all 'Z' from the address and de-capitalize it).

Compute diagrams

To use CalIph, follow these steps:

  1. Load a TDB file (from your computer, or selected below; you can find many at the ThermoDynamic DataBase DataBase, which gathers the condensed phases thermodynamic data freely available in electronic form).
  2. Select the two elements for which you want to display the binary phase diagram (use Ctrl+Click).
  3. Click on Convert, and the mixing enthalpies are then displayed in the text box.
  4. Click on Solve, and the certified phase diagram is calculated then displayed; The computation may take a while, a log allows you to follow its status.

You can then play around with the graphic visualization that conveniently allows to select/unselect phases, zoom on a region of interest, display the coordinates of a point under the mouse cursor, etc. Click on the export button (camera icon) to get a camera-ready .png of your graphic.

Demonstration with predefined TDB

Choose a predefined TDB in the selection list, it will be solved using CalIPh software program.

Use your own TDB

Choose your own TDB from your hard disk, it will be uploaded to the server and solved using CalIPh software program. The maximum file size is set to 500ko.


Release notes

This tool has been jointly developed by Thomas Gouhier, Alexandre Goldsztejn, Christophe Jermann and Damien Vintache (LS2N, Nantes), and Isabelle Braems (IMN, Nantes).