TCHEA8 Elements, Systems, and Phases
This section summarizes the available elements, assessed systems, and total number of phases in the TCS High Entropy Alloys Database (TCHEA).
Included Elements
The database is developed in a 27 element framework:
| Elements | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Al | B | C | Co | Cr | Cu | Fe | Hf | Ir | Mn |
| Mo | N | Nb | Ni | O | Re | Rh | Ru | Si | Sn |
| Ta | Ti | V | W | Y | Zn | Zr | |||
Assessed Systems and Phases
The most recent version of the database contains:
- 342 binary systems, with almost all of these assessed to the full range of composition and temperature. These can be calculated with the BINARY module in Thermo‑Calc Console Mode.
- 643 ternary systems are assessed, and 218 of them to the full range of composition and temperature. These can be calculated with the TERNARY module in Thermo‑Calc Console Mode.
- 54 quaternary systems and 3 higher order systems are assessed.
- 713 solution and intermetallic phases, where nearly all stable phases in all assessed binary systems and most ternary systems are modeled.
About the Included Phases
The ordered B2 and L12 phases, together with BCC_A2 and FCC_A1, respectively, are modeled with the so-called partitioning model, which describes an ordered phase and its disordered counterpart using a single Gibbs energy curve. This type of description is of particular importance to be able to predict second order transformations between a disordered phase and its ordered structures.
Also note that there may be several possible composition sets for the phases named FCC_L12 and BCC_B2 designated by #1, #2, and so on (e.g. FCC_L12#1 and FCC_L12#2), due to the co-existence of disordered and ordered structures or the presence of miscibility gap. The #n suffix (where n is an integer) is generated dynamically by Thermo‑Calc when using global minimization and therefore the identification of the phases should be determined from their site occupations. It can be found by LIST_EQUILIBRIUM with the VXNS option in the Console Mode or showing the site fraction in moles of the constituent elements in the Graphical Mode. When the site occupancies of the first and second sublattices are equal the phase is disordered.
In Console Mode, you can list phases and constituents in the Database (TDB) module and the Gibbs (GES) module. For some phases, supplementary information is included in the definitions. To show the information, it is recommended in the Database (TDB) module to use the command List_System with the option Constituents.