The CALPHAD Approach

CALPHAD is originally an abbreviation for CALculation of PHAse Diagrams, but was later expanded to refer to computer coupling of phase diagrams and thermochemistry. More about the CALPHAD methodology, including some of its history, is available on the Thermo‑Calc Software website.

The data optimization functionality in Thermo‑Calc works according to the CALPHAD approach to computational thermodynamics. This approach builds on the development of models that accurately represent thermodynamic properties for various phases. These models enable you to predict the thermodynamic properties of multicomponent systems-based data concerning binary and ternary subsystems. The predictions can take many factors into accounts, such as, for example, crystallography, type of bonding, order-disorder transitions and magnetic properties.

References

For in-depth information about CALPHAD as well as data optimization, see Computational Thermodynamics – The Calphad Method by Hans Leo Lukas, Suzana G. Fries and Bo Sundman (Cambridge University Press, 2007). CALPHAD was given its first general description in Computer Calculations of Phase Diagrams by Larry Kaufman and Harold Bernstein (Academic Press, 1970). The book contains some case studies of optimizations using Thermo‑Calc.

Information about the concept of ‘lattice stability’ (which is important for the development of multicomponent thermodynamic databases) can also be found in the paper Hume-Rothery and Calphad Thermodynamics by Larry Kaufman, published in Calphad and Alloy Thermodynamics, edited by Patrice E.A. Turchi, Antonios Gonis, Robert Shull (The Minerals, Metals & Materials Society, 2002), pp. 3-19.