TCHEA: TCS High Entropy Alloys Database Revision History

Software release version 2025b (June 2025)

Elements and Phases

• Added O (oxygen) making it a 27 element framework.
• 173 new phases (713 phases in total)

Elastic Properties

• Added elastic properties for BCC (A2 & B2), FCC (A1 & L12), and HCP (A3) phases.

Binary Systems

• 26 newly assessed M-O binaries, where M = Al, B, C, Co, Cr, Cu, Fe, Hf, Ir, Mn, Mo, N, Nb, Ni, Re, Rh, Ru, Si, Sn, Ta, Ti, V, W, Y, Zn, and Zr.
• Updated 11 assessed binaries: Al-Fe, Al-Ni, B-Nb, Cr-Ti, Fe-Ni, Fe-Ti, Mo-Nb, Mo-Ta, Mo-W, Nb-W, and Ta-W.

Ternary Systems

• 117 new ternary assessments, mainly related to O containing systems especially in oxide pseudo-binaries.
• Reassessed 3 metallic ternary systems: Al-Fe-Ni, Cr-Fe-Ti, and Cr-Nb-Ti.

Quaternary Systems

• Added 54 quaternary assessments, mainly related to O containing systems especially in oxide pseudo-ternaries, but also for metallic systems e.g. Mo-Nb-Ta-W.

Higher Order Systems

• 3 new higher order systems added: Al-Fe-Mn-O-Si, C-Cr-Fe-Mn-Ni-O, and Co-Cr-Fe-Mn-Ni.

Thermophysical Properties

• Added/updated viscosity, surface tension and THCD/ELRS descriptions of the liquid phase for the above newly-added/updated systems.
• Added/updated ELRS-THCD description for all the phases including intermetallic phases in addition of BCC (A2 & B2), FCC (A1 & L12) and HCP (A3) solution phases.

Software release 2024a (December 2023/January 2024)

Binary Systems

• Newly assessed Mo-Sn, N-Y, Rh-Nb, Rh-Si, Rh-Ta, Rh-V, and Rh-Y.
• Reassessed Mn-W.

Ternary Systems

• Newly assessed Nb-V-Zr and V-W-Zr
• Revision of SIGMA phase stability: Al-Co-Cr, Al-Co-V, Al-Cr-Ni, Al-Cr-V, Al-Fe-Ni, Al-Fe-V, Al-Mo-Ni, Al-Mo-V, Al-Ni-V, Co-Cr-V, Co-Fe-V, Co-Mo-V, Cr-Fe-V, Fe-Mo-Ni, Fe-Mo-V, and Mo-Ni-V.
• Revision of BCC phase stability: Co-Cr-Ti, Co-Cu-Nb, Co-Cu-Ni, Co-Ni-Si, Co-Ni-V, Co-Ni-W, Cr-Cu-Si, Cr-Mo-Ni, Cr-Ni-Si, Cu-Fe-Ni, Cu-Mo-Ni, Fe-Ni-Ti, Fe-Ni-W, and Ni-Si-Ti.
• Revision of FCC phase stability: Al-Co-Zr, Al-Cr-Ti, Al-Fe-Ti, Al-Hf-Ti, Al-Mn-Ti, Al-Mo-Ti, Al-Nb-Ti, Al-Si-Ti, Al-Sn-Ti, Al-Ta-Ti, Al-Ti-Zr, Al-V-Zr, Co-Ta-Ti, Cr-Cu-Mo, Cr-Cu-Zr, Cr-Fe-Si, Cr-Fe-V, Cr-Mo-Nb, Cr-Ti-Zr, Fe-Ni-V, Fe-Ti-V, Mo-Nb-Ti, Mo-Ni-Ti, Mo-Re-Ta, Mo-Ta-Ti, Mo-Ti-W, Mo-Ti-Zr, Nb-Ti-W, Si-Ti-W, Ta-Ti-V, Ti-V-W, and Ti-V-Zr.
• Revision of HCP phase stability: Al-Co-Ni, Al-Co-W, Al-Co-Zr, Al-Cr-Ni, Al-Cu-Ni, Al-Fe-Mn, Al-Fe-Ni, Al-Nb-Ni, Al-Ni-Si, Al-Ni-Ti, Al-Ni-W, Al-Ni-Zn, Co-Cr-Ti, Co-Cu-Fe, Co-Cu-Nb, Co-Cu-Ni, Co-Ni-V, Co-Ni-W, Co-Ta-Ti, Cr-Cu-Mo, Cr-Cu-Nb, Cr-Cu-Si, Cr-Cu-Zr, Cr-Fe-Mo, Cr-Fe-Ni, Cr-Fe-Si, Cr-Fe-V, Cr-Mo-Nb, Cr-Mo-Ni, Cr-Ni-Re, Cr-Ni-Si, Cr-Ni-W, Cr-Ti-Zr, Cu-Fe-Mn, Cu-Fe-Ni, Cu-Fe-Si, Cu-Fe-Sn, Cu-Fe-V, Cu-Mn-Ni, Cu-Mn-Si, Cu-Mn-Sn, Cu-Mo-Ni, Cu-Ni-Ti, Cu-Ni-Zn, Fe-Mo-Ni, Fe-Ni-Ti, Fe-Ni-V, Fe-Ni-W, Hf-Ni-Ti, Mo-Nb-Ti, Mo-Ni-Ti, Mo-Re-Ta, Mo-Ti-W, Mo-Ti-Zr, Ni-Si-Ti, Si-Ti-W, Ta-Ti-V, and Ti-V-W.
• Revision of LIQUID phase stability: Al-Cr-Ti, Mo-Nb-Ti, Mo-Ni-Ti, Mo-Re-Ru, Mo-Re-Ta, Mo-Ta-Ti, Ta-Ti-V, and Ti-V-W.

Surface Tension Re-assessed

The surface tension was re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model.

Software release 2023a (December 2022/January 2023)

Reassessed Binary, Ternary, and Quinary Systems

• Binary: Two reassessments, Cr-Mn, Ir-Nb.
• Ternary: Seventeen (re-)assessments: Al-Cr-V, Co-Cr-Fe, Co-Cr-Mn, Co-Cr-Ni, Co-Fe-Mn, Co-Fe-Ni, Co-Mn-Ni, Cr-Fe-Mn, Cr-Mn-Ni, Cr-Mo-Nb, Cr-Mo-Ti, Cr-Nb-V, Fe-Mn-Ni, Fe-Ni-W, Mo-Nb-V, Re-Nb-V, and Re-V-W.
• Quinary: Validation of the Co-Cr-Fe-Mn-Ni system in full temperature and composition space (7 isopleths).

Software release version: 2022b (June 2022)

In this release of the database, there is one new ternary system assessment plus major changes to 18 critically assessed systems. In addition, 19 ternary systems also had some minor changes and a complete description of the gas phase is added.

• 1 new ternary assessment added: Al-V-Zr.
• Reassessed 18 ternary systems: Al-Co-Ti, Al-Cr-Ti, Al-Mn-Ti, Al-Mo-Ti, Al-Ni-Ti, Al-Sn-Ti, Al-Ta-Ti, Al-V-Zr, Co-Mo-Ti, Cr-Mn-Ti, Cr-Ti-Zr, Fe-Ti-V, Mo-Ti-V, Mo-Ti-Zr, Nb-Ti-W, Ta-Ti-V, Ti-V-W, and Ti-V-Zr.
• Minor modifications to 19 ternary systems: Al-B-Ti, Al-C-Ti, Al-Fe-Ti, Al-N-Ti, Al-Si-Ti, Co-Sn-Ti, Cr-Si-Ti, Cu-Ti-Zr, Mo-Nb-Ti, Mo-Ta-Ti, Mo-Ti-W, Nb-Sn-Ti, Nb-Ta-Ti, Nb-Ti-V, Nb-Ti-Zr, Si-Ti-W, Ta-Ti-W, Ta-Ti-Zr, and Ti-W-Zr.
• Added a complete description of the gas phase in the 26 element framework.

Software release version: 2022a (December 2021/January 2022)

• Improved the BCC (A2/B2) phase descriptions in the framework of the Al-Cr-Nb-Ti-V-Zr system. Updated assessments of the Al-V, Mo-V, and Ti-V binaries. Updated assessments of the Al-Nb-Ti, Al-Ti-V, and Al-Ti-Zr ternaries.
• Improved the MC carbide description in the framework of the (Hf, Nb, Ta, Ti, V, Zr)C system. Added assessments of the C-Hf-Nb, C-Hf-V, C-Nb-Ta, C-Ta-V, C-Ta-Zr, C-Ti-V, and C-V-Zr ternaries. Updated assessment of the C-Hf-Ta, C-Hf-Ti, C-Nb-Ti, C-Nb-V, C-Nb-Zr, and C-Ti-Zr ternaries.
• Minor bug fixed for ternary-related calculations of the Al-Fe-W, Al-Hf-Nb, Al-Mo-Nb, and Al-Mo-Ni systems.

Software release version: 2021b (June 2021)

• Addition of surface tension of liquid phase.
• Addition of electrical resistivity and thermal conductivity of liquid, BCC (A2, B2), FCC (A1, L12), and HCP solution phases.

Software release version: 2021a (January 2021)

• Added the assessment of three binary systems- Ir-W, Mo-Rh, and Rh-W.

Software release version: 2020b (June 2020)

• Crystal structure information is included for all phases.
• HCP_ZN is merged into HCP_A3. The epsilon phase with HCP structure in the Cu-Zn, Mn-Zn and Cu-Mn-Zn systems is separated from HCP_A3 and renamed as CUMNZN_EPSILON_HCP.
• Better estimation of excess energy for metastable solution phases and compound energy for metastable end-members in binary systems.

Software release version: 2020a (January 2020)

• 49 ternaries added.
• 12 ternaries improved.
• 13 binaries added (mainly Ir-,or Rh-).
• 1 binary updated (Al-Ti).
• Includes the viscosity of metallic liquid data.

Software release 2019a (December 2018).

• The Mn-Ni-Si ternary is critically assessed in full composition and temperature ranges.
• Some bug fixes e.g. avoid the fictitious HCP_ZN phase appears in Zn-free systems, adjust the phase stability of GAMMA_D03, CRSI2_C40, C15- & C36- laves phases in some systems.

Software release version: 2018a (April 2018)

• 6 new elements (B, Ir, Rh, Sn, Y and Zn) added.
• More than 100 new binary systems and >150 new phases added.

• The database has improved stability description of the sigma phase.

• Added 5 new elements (C, N, Re, Ru, Si) and 100 phases.
• Assessed most of new binary systems that contain one or two of these 5 new elements in the 20-element framework of this database.
• Assessed 200 additional ternary systems relevant to the 5 new elements.
• The application of TCHEA2 extends from BCC and FCC HEAs to HCP HEA as well.
• Revised some subsystems based on the validation against updated experimental information. This includes the phase stability of solid solutions such as BCC and FCC and intermetallic phases such as sigma and laves in some ternary and quaternary systems.