Software for calculation of phase diagrams and thermodynamic properties have been developed since the 1970's. Software and computers have now developed to a level where such calculations can be used as tools for material and process development. In the present paper some of the latest software developments at Thermo-Calc Software are presented together with application examples. It is shown how advanced thermodynamic calculations have become more accessible since: - A more user-friendly windows version of Thermo-Calc, TCW, has been developed. - There is an increasing amount of thermodynamic databases for different materials available. - Thermo-Calc can be accessed from user-written software through several different programming interfaces are available which enables access to the thermodynamic software from a user-written software. Accurate data for thermodynamic properties and phase equilibria can then easily be incorporated into software written in e.g. C++, Matlab and FORTRAN. Thermo-Calc Software also produces DICTRA, a software for simulation of diffusion controlled phase transformations. Using DICTRA it is possible to simulate processes such as homogenization, carburising, microsegregation and coarsening in multicomponent alloys. The different models in the DICTRA software are briefly presented in the present paper together with some application examples.

Thermo-Calc & DICTRA, computational tools for materials science

An introductory review of various concepts about first-order phase transitions is given. Rules for classification of phase transitions as second or first order are discussed, as well as exceptions to these rules. Attention is drawn to the rounding of first-order transitions due to finite-size or quenched impurities. Computational methods to calculate phase diagrams for simple model Hamiltonians are also described. Particular emphasis is laid on metastable states near first-order phase transitions, on the 'stability limits' of such states (e.g. the 'spinodal curve' of the gas-liquid transition) and on the dynamic mechanisms by which metastable states decay (nucleation and growth of droplets of a new phase, etc.).

https://iopscience.iop.org/article/10.1088/0034-4885/50/7/001/pdf

Theory of first-order phase transitions

A long-standing limitation of first-principles calculations of substitutional alloy phase diagrams is the difficulty in accounting for lattice vibrations. A survey of the theoretical and experimental literature seeking to quantify the effect of lattice vibrations on phase stability indicates that they can be significant. Typical vibrational entropy differences between phases are of the order of 0.1 to 0.2kB/atom, which is comparable to the typical values of configurational entropy differences in binary alloys (at most 0.693kB/atom). This article presents the basic formalism underlying ab initio phase diagram calculations, along with the generalization required to account for lattice vibrations. The authors review the various techniques allowing the theoretical calculation and the experimental determination of phonon dispersion curves and related thermodynamic quantities, such as vibrational entropy or free energy. A clear picture of the origin of vibrational entropy differences between phases in an alloy system is presented that goes beyond the traditional bond counting and volume change arguments. Vibrational entropy change can be attributed to the changes in chemical bond stiffness associated with the changes in bond length that take place during a phase transformation. This so-called “bond stiffness vs bond length” interpretation both summarizes the key phenomenon driving vibrational entropy changes and provides a practical tool to model them.

/pdf/the-effect-of-lattice-vibrations-on-substitutional-alloy-3hrglj9kqz.pdf

The effect of lattice vibrations on substitutional alloy thermodynamics

Get the phase diagram information you need at a price you can afford. Key Features: Peer reviewed by the Japanese Committee for Alloy Phase Diagrams. Updated through April 2000. Total number of diagrams = 2,332 (605 are new of greatly revised diagrams; among these 171 are not in Binary Alloy Phase Diagrams, 2nd Edition). Approximately 600 crystal structure tables of systems for which phase diagrams are unknown. You've been asking for a simple book containing just binary phase diagrams and crystal structure data. Desk Handbook: Phase Diagrams for Binary Alloys meets this need, and it presents the most current information. Updates the previous print compilation of binary phase diagrams by 10 years. Presents diagrams in consistent size. Shows the principal axis in atomic per cent, with a secondary axis in weight per cent. Includes an introductory article on phase diagrams and their use. Gives reference to the original literature source. This volume is the latest outgrowth of the phase diagram activity in which ASM International has been involved since 1978.

Desk handbook phase diagrams for binary alloys

IN view of the interest attaching to the vaporisation and diffusion of solids, the following observations may be worthy of record.

The Diffusion of Solids

Overview no. 43. Binary ordering prototype phase diagrams in the cluster variation approximation

On demontre que les calculs de structure electronique utilisant l'approximation de densite locale dans la theorie de la fonctionnelle de densite rend compte des comportements distinctement differents dans les diagrammes de phases d'equilibre dans les alliages consideres. On fait une analyse microscopique detaillee basee sur la prescription proposee par Connolly et Williams

Electronic theory of the alloy phase stability of Cu-Ag, Cu-Au, and Ag-Au systems

https://escholarship.org/content/qt7t1781w7/qt7t1781w7.pdf?t=p0fuqz

Short range order diffuse intensity calculations in the cluster variation method

Mechanical properties of L1 2 -Co 3 (A1,W) polycrystalline sample are investigated by compression testing at various temperature ranging from room temperature to 1193 K. It was found that at room temperature the 0.2% flow stress is 410 MPa and the compressive ductility is higher than 10%, whereas at 1193K the 0.2% flow stress is 382 MPa and the compressive ductility is about 10%. Two candidates for the reaction scheme of the Co-rich region of the Co-Al-W ternary phase diagram are proposed by combining the results of microstructure observation, X-ray diffractometry and the previous report.

https://www.jstage.jst.go.jp/article/matertrans/48/9/48_MAW200734/_pdf

Tetsuo Mohri

Papers

Overview no. 43. Binary ordering prototype phase diagrams in the cluster variation approximation

Electronic theory of the alloy phase stability of Cu-Ag, Cu-Au, and Ag-Au systems

Short range order diffuse intensity calculations in the cluster variation method

Mechanical properties of co-based L12 intermetallic compound Co3(Al,W)

Thermal conductivity of B2-type aluminides and titanides