Computational thermodynamics is the use of computers to simulate

thermodynamic Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of t ...

problems specific to materials science, particularly used in the construction of phase diagrams. Several open and commercial programs exist to perform these operations. The concept of the technique is minimization of

Gibbs free energy In thermodynamics, the Gibbs free energy (or Gibbs energy; symbol G) is a thermodynamic potential that can be used to calculate the maximum amount of work (physics), work that may be performed by a closed system, thermodynamically closed system a ...

of the system; the success of this method is due not only to properly measuring thermodynamic properties, such as those in the

list of thermodynamic properties In thermodynamics, a physical property is any property that is measurable, and whose value describes a state of a physical system. Thermodynamic properties are defined as characteristic features of a system, capable of specifying the system's stat ...

, but also due to the extrapolation of the properties of metastable allotropes of the

chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...

History

The computational modeling of metal-based phase diagrams, which dates back to the beginning of the previous century mainly by Johannes van Laar and to the modeling of regular solutions, has evolved in more recent years to the CALPHAD (CALculation of PHAse Diagrams). This has been pioneered by American

metallurgist Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sci ...

Larry Kaufman since the 1970s.

Current state

Computational thermodynamics may be considered a part of materials informatics and is a cornerstone of the concepts behind the

materials genome Materials genome is an analogy to genomes in biology, but in a conceptual sense: the many important phases, defects, and processes that make up engineered materials are the "genome" of materials science. The Materials Genome Initiative (MGI) is an ...

project. While crystallographic databases are used mainly as a reference source, thermodynamic databases represent one of the earliest examples of informatics, as these databases were integrated into thermochemical computations to map phase stability in binary and ternary

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...

s. Many concepts and software used in computational thermodynamics are credited to the SGTE Group, a consortium devoted to the development of thermodynamic databases; the open elements database is freely available based on the paper by Dinsdale. This so-called "unary" system proves to be a common basis for the development of binary and multiple systems and is used by both commercial and open software in this field. However, as stated in recent CALPHAD papers and meetings, such a Dinsdale/SGTE database will likely need to be corrected over time despite the utility in keeping a common base. In this case, most published assessments will likely have to be revised, similarly to rebuilding a house due to a severely broken foundation. This concept has also been depicted as an "inverted pyramid." Merely extending the current approach (limited to temperatures above room temperature) is a complex task. PyCalphad, a Python library, was designed to facilitate simple computational thermodynamics calculation using open source code. In complex systems, computational methods such as CALPHAD are employed to model thermodynamic properties for each phase and simulate multicomponent phase behavior. The application of CALPHAD to high pressures in some important applications, which are not restricted to one side of materials science like the Fe-C system, confirms experimental results by using computational thermodynamic calculations of phase relations in the Fe–C system at high pressures. Other scientists even considered

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

and other physical parameters, which are beyond the domain of thermodynamics.

Future developments

There is still a gap between ab initio methods and operative computational thermodynamics databases. In the past, a simplified approach introduced by the early works of Larry Kaufman, based on

Miedema's Model Miedema's model is a semi-empirical approach for estimating the heat of formation of solid or liquid metal alloys and compounds in the framework of thermodynamic calculations for metals and minerals. It was developed by the Dutch scientist Andries ...

, was employed to check the correctness of even the simplest binary systems. However, relating the two communities to

Solid State Physics Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the l ...

and Materials Science remains a challenge, as it has been for many years. Promising results from ab initio

quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, q ...

molecular simulation packages like VASP are readily integrated in thermodynamic databases with approaches like Zentool.http://zengen.cnrs.fr/manual.pdf A relatively easy way to collect data for intermetallic compounds is now possible by using Open Quantum Materials Database.

References

External links

*
Official CALPHAD website
*
Python-based libraries for the calculation of phase diagrams and thermodynamic properties

* ttp://www.opencalphad.com/ Open Calphad
Thermocalc for Students

Pandat (free up to three components)

Matcalc (free up to three components, open databases available)

NIST

Thermodynamic Modeling using the Calphad Method
at

ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , a ...

MELTS Software for thermodynamic modeling of phase equilibria in magmatic systems

SGTE Scientific Group Thermodata Europe

Larry Kaufman at Hmolpedia
* * *{{cite journal , last1=Kirklin , first1=Scott , last2=Saal , first2=James E. , last3=Meredig , first3=Bryce , last4=Thompson , first4=Alex , last5=Doak , first5=Jeff W. , last6=Aykol , first6=Muratahan , last7=Rühl , first7=Stephan , last8=Wolverton , first8=Chris , title=The Open Quantum Materials Database (OQMD): assessing the accuracy of DFT formation energies , journal=NPJ Computational Materials , date=11 December 2015 , volume=1 , issue=1 , pages=15010 , doi=10.1038/npjcompumats.2015.10 , bibcode=2015npjCM...115010K , doi-access=free * pen Quantum Materials Database http://oqmd.org

University Courses on Computational Thermodynamics