# Co–Fe phases > Co–Fe system: 5 phases (tier A 4, liquid 1); 5 stable in a calculated diagram in the ORCHID phase registry, with names, structure type when the stored evidence supports an assignment under the stated tier rules, calculated stability, verbatim TDB PHASE/CONSTITUENT statements and example references. HTML: https://data.orchid-project.org/phases/pages/CO-FE.html · Markdown: https://data.orchid-project.org/phases/pages/CO-FE.md 5 phases (tier A 4, liquid 1); 5 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model). Data: [interactive registry](https://orchid-project.org/phases/?q=CO-FE) · [full JSON](https://data.orchid-project.org/phases/systems/CO-FE.json) · [Co–Fe system page](https://data.orchid-project.org/systems/CO-FE.html) · [Markdown](https://data.orchid-project.org/phases/pages/CO-FE.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md) Table: Phases of the Co–Fe system (5) | Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models | |---|---|---|---|---:|---:| | [BCC_A2](#phase-co-fe-bcc-a2); _phase:co-fe:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 4 of 4 calculated diagram(s): 300–1810.95 K, x(Fe) 0.18484–1 | 0 | 6 | | [B2_BCC](#phase-co-fe-bcc-b2); _phase:co-fe:bcc-b2_ | CsCl · B2 · cP2 · Pm-3m (221) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 300–1810.95 K, x(Fe) 0.23523–1 | 0 | 2 | | [FCC_A1](#phase-co-fe-fcc-a1); _phase:co-fe:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 4 of 4 calculated diagram(s): 406.16–1777.77 K, x(Fe) 0–1 | 0 | 4 | | [HCP_A3](#phase-co-fe-hcp-a3); _phase:co-fe:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | stable in 4 of 4 calculated diagram(s): 300–779.98 K, x(Fe) 0–0.03623 | 0 | 4 | | [LIQUID](#phase-co-fe-liquid); _phase:co-fe:liquid_ | liquid | liquid | stable in 4 of 4 calculated diagram(s): 1745.93–2500 K, x(Fe) 0–1 | 0 | 4 | ## BCC_A2 (Co–Fe) - Id: `phase:co-fe:bcc-a2`; status `assigned` - Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high - Stability: stable in 4 of 4 calculated diagram(s): 300–1810.95 K, x(Fe) 0.18484–1 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-fe:bcc-a2) Names (7): _corpus: _corpus:phase:co-fe:bcc-a2 _tdb: _tdb:CoFe-02Ohn.tdb:A2_BCC, tdb:CoFe-02Ohn.tdb:BCC_A2, tdb:CoFe-15Rod.tdb:BCC_A2, tdb:CoFe-17Wan.tdb:A2_BCC, tdb:CoFe-17Wan.tdb:BCC_A2, tdb:CoFe-87Fer-LB.tdb:BCC_A2 ### TDB models of BCC_A2 (6): PHASE and CONSTITUENT statements as written [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): A2_BCC, type code %B, sha256 `4ed3ddb5c0d6db77…` ~~~~text 40: PHASE A2_BCC %B 2 1 3 ! 41: CONST A2_BCC : CO FE : VA : ! ~~~~ [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): BCC_A2, type code %B, sha256 `4ed3ddb5c0d6db77…` ~~~~text 35: PHASE BCC_A2 %B 2 1 3 ! 36: CONST BCC_A2 : CO FE% : VA : ! ~~~~ [CoFe-15Rod.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-15Rod.tdb): BCC_A2, type code %B, sha256 `b439f24ad16996c6…` ~~~~text 33: PHASE BCC_A2 %B 2 1 3 ! 34: CONST BCC_A2 : CO FE% : VA : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): A2_BCC, type code %B, sha256 `324b5028ec03d395…` ~~~~text 37: PHASE A2_BCC %B 2 1 3 ! 38: CONST A2_BCC : CO FE : VA : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): BCC_A2, type code %B, sha256 `324b5028ec03d395…` ~~~~text 32: PHASE BCC_A2 %B 2 1 3 ! 33: CONST BCC_A2 : CO FE% : VA : ! ~~~~ [CoFe-87Fer-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-87Fer-LB.tdb): BCC_A2, type code %B, sha256 `edf9a6fc99f8e55a…` ~~~~text 31: PHASE BCC_A2 %B 2 1 3 ! 32: CONST BCC_A2 : CO FE% : VA : ! ~~~~ Example references (3 of 3; assessments first): - [doi:10.1016/j.calphad.2015.03.001](https://doi.org/10.1016/j.calphad.2015.03.001) Justin E. Rodriguez, Douglas M. Matson, Thermodynamic modeling of the solidification path of levitated Fe–Co alloys, Calphad 49, 87-100 (2015). _assessment that models this phase_ - [doi:10.1016/j.calphad.2017.06.001](https://doi.org/10.1016/j.calphad.2017.06.001) J. Wang, X.-G. Lu, N. Zhu, W. Zheng, Calphad, 58, 82-100(2017). _assessment that models this phase_ - [doi:10.1016/S1359-6454(01)00337-8](https://doi.org/10.1016/S1359-6454%2801%2900337-8) I. Ohnuma, H. Enoki, O. Ikeda, R. Kainuma, H. Ohtani, B. Sundman, K. Ishida, Acta Mater., 50, 379-93(2002). _assessment that models this phase_ ## B2_BCC (Co–Fe) - Id: `phase:co-fe:bcc-b2`; status `assigned` - Structure: CsCl · B2 · cP2 · Pm-3m (221); type `st:b2-cscl-cp2`; tier A: standard phase name; confidence high - Caveat: CoFe-02Ohn.tdb: ordered phase with disordered part A2_BCC (order/disorder model) - Caveat: CoFe-17Wan.tdb: ordered phase with disordered part A2_BCC (order/disorder model) - Caveat: partitioned order/disorder model in CoFe-02Ohn.tdb also describes the disordered state - Caveat: partitioned order/disorder model in CoFe-17Wan.tdb also describes the disordered state - Stability: stable in 2 of 2 calculated diagram(s): 300–1810.95 K, x(Fe) 0.23523–1 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-fe:bcc-b2) Names (3): _corpus: _corpus:phase:co-fe:bcc-b2 _tdb: _tdb:CoFe-02Ohn.tdb:B2_BCC, tdb:CoFe-17Wan.tdb:B2_BCC ### TDB models of B2_BCC (2): PHASE and CONSTITUENT statements as written [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): B2_BCC, type code %BO, sha256 `4ed3ddb5c0d6db77…` ~~~~text 45: PHASE B2_BCC %BO 3 0.5 0.5 3 ! 46: CONST B2_BCC : CO% FE : CO FE% : VA : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): B2_BCC, type code %BO, sha256 `324b5028ec03d395…` ~~~~text 42: PHASE B2_BCC %BO 3 0.5 0.5 3 ! 43: CONST B2_BCC : CO% FE : CO FE% : VA : ! ~~~~ Example references (2 of 2; assessments first): - [doi:10.1016/j.calphad.2017.06.001](https://doi.org/10.1016/j.calphad.2017.06.001) J. Wang, X.-G. Lu, N. Zhu, W. Zheng, Calphad, 58, 82-100(2017). _assessment that models this phase_ - [doi:10.1016/S1359-6454(01)00337-8](https://doi.org/10.1016/S1359-6454%2801%2900337-8) I. Ohnuma, H. Enoki, O. Ikeda, R. Kainuma, H. Ohtani, B. Sundman, K. Ishida, Acta Mater., 50, 379-93(2002). _assessment that models this phase_ ## FCC_A1 (Co–Fe) - Id: `phase:co-fe:fcc-a1`; status `assigned` - Structure: Cu · A1 · cF4 · Fm-3m (225); type `st:a1-cu-cf4`; tier A: standard phase name; confidence high - Stability: stable in 4 of 4 calculated diagram(s): 406.16–1777.77 K, x(Fe) 0–1 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-fe:fcc-a1) Names (5): _corpus: _corpus:phase:co-fe:fcc-a1 _tdb: _tdb:CoFe-02Ohn.tdb:FCC_A1, tdb:CoFe-15Rod.tdb:FCC_A1, tdb:CoFe-17Wan.tdb:FCC_A1, tdb:CoFe-87Fer-LB.tdb:FCC_A1 ### TDB models of FCC_A1 (4): PHASE and CONSTITUENT statements as written [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): FCC_A1, type code %A, sha256 `4ed3ddb5c0d6db77…` ~~~~text 30: PHASE FCC_A1 %A 2 1 1 ! 31: CONST FCC_A1 : CO% FE% : VA : ! ~~~~ [CoFe-15Rod.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-15Rod.tdb): FCC_A1, type code %A, sha256 `b439f24ad16996c6…` ~~~~text 28: PHASE FCC_A1 %A 2 1 1 ! 29: CONST FCC_A1 : CO% FE% : VA : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): FCC_A1, type code %A, sha256 `324b5028ec03d395…` ~~~~text 27: PHASE FCC_A1 %A 2 1 1 ! 28: CONST FCC_A1 : CO% FE% : VA : ! ~~~~ [CoFe-87Fer-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-87Fer-LB.tdb): FCC_A1, type code %A, sha256 `edf9a6fc99f8e55a…` ~~~~text 26: PHASE FCC_A1 %A 2 1 1 ! 27: CONST FCC_A1 : CO% FE% : VA : ! ~~~~ Example references (3 of 3; assessments first): - [doi:10.1016/j.calphad.2015.03.001](https://doi.org/10.1016/j.calphad.2015.03.001) Justin E. Rodriguez, Douglas M. Matson, Thermodynamic modeling of the solidification path of levitated Fe–Co alloys, Calphad 49, 87-100 (2015). _assessment that models this phase_ - [doi:10.1016/j.calphad.2017.06.001](https://doi.org/10.1016/j.calphad.2017.06.001) J. Wang, X.-G. Lu, N. Zhu, W. Zheng, Calphad, 58, 82-100(2017). _assessment that models this phase_ - [doi:10.1016/S1359-6454(01)00337-8](https://doi.org/10.1016/S1359-6454%2801%2900337-8) I. Ohnuma, H. Enoki, O. Ikeda, R. Kainuma, H. Ohtani, B. Sundman, K. Ishida, Acta Mater., 50, 379-93(2002). _assessment that models this phase_ ## HCP_A3 (Co–Fe) - Id: `phase:co-fe:hcp-a3`; status `assigned` - Structure: Mg · A3 · hP2 · P6_3/mmc (194); type `st:a3-mg-hp2`; tier A: standard phase name; confidence high - Stability: stable in 4 of 4 calculated diagram(s): 300–779.98 K, x(Fe) 0–0.03623 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-fe:hcp-a3) Names (5): _corpus: _corpus:phase:co-fe:hcp-a3 _tdb: _tdb:CoFe-02Ohn.tdb:HCP_A3, tdb:CoFe-15Rod.tdb:HCP_A3, tdb:CoFe-17Wan.tdb:HCP_A3, tdb:CoFe-87Fer-LB.tdb:HCP_A3 ### TDB models of HCP_A3 (4): PHASE and CONSTITUENT statements as written [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): HCP_A3, type code %A, sha256 `4ed3ddb5c0d6db77…` ~~~~text 50: PHASE HCP_A3 %A 2 1 0.5 ! 51: CONST HCP_A3 : CO% FE : VA : ! ~~~~ [CoFe-15Rod.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-15Rod.tdb): HCP_A3, type code %A, sha256 `b439f24ad16996c6…` ~~~~text 38: PHASE HCP_A3 %A 2 1 0.5 ! 39: CONST HCP_A3 : CO% FE : VA : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): HCP_A3, type code %A, sha256 `324b5028ec03d395…` ~~~~text 47: PHASE HCP_A3 %A 2 1 0.5 ! 48: CONST HCP_A3 : CO% FE : VA : ! ~~~~ [CoFe-87Fer-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-87Fer-LB.tdb): HCP_A3, type code %A, sha256 `edf9a6fc99f8e55a…` ~~~~text 36: PHASE HCP_A3 %A 2 1 0.5 ! 37: CONST HCP_A3 : CO% FE : VA : ! ~~~~ Example references (3 of 3; assessments first): - [doi:10.1016/j.calphad.2015.03.001](https://doi.org/10.1016/j.calphad.2015.03.001) Justin E. Rodriguez, Douglas M. Matson, Thermodynamic modeling of the solidification path of levitated Fe–Co alloys, Calphad 49, 87-100 (2015). _assessment that models this phase_ - [doi:10.1016/j.calphad.2017.06.001](https://doi.org/10.1016/j.calphad.2017.06.001) J. Wang, X.-G. Lu, N. Zhu, W. Zheng, Calphad, 58, 82-100(2017). _assessment that models this phase_ - [doi:10.1016/S1359-6454(01)00337-8](https://doi.org/10.1016/S1359-6454%2801%2900337-8) I. Ohnuma, H. Enoki, O. Ikeda, R. Kainuma, H. Ohtani, B. Sundman, K. Ishida, Acta Mater., 50, 379-93(2002). _assessment that models this phase_ ## LIQUID (Co–Fe) - Id: `phase:co-fe:liquid`; status `assigned` - Structure: liquid; type `st:liquid`; liquid; confidence high - Stability: stable in 4 of 4 calculated diagram(s): 1745.93–2500 K, x(Fe) 0–1 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-fe:liquid) Names (5): _corpus: _corpus:phase:co-fe:liquid _tdb: _tdb:CoFe-02Ohn.tdb:LIQUID, tdb:CoFe-15Rod.tdb:LIQUID, tdb:CoFe-17Wan.tdb:LIQUID, tdb:CoFe-87Fer-LB.tdb:LIQUID ### TDB models of LIQUID (4): PHASE and CONSTITUENT statements as written [CoFe-02Ohn.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-02Ohn.tdb): LIQUID, type code %, sha256 `4ed3ddb5c0d6db77…` ~~~~text 25: PHASE LIQUID:L % 1 1 ! 26: CONST LIQUID:L : CO FE : ! ~~~~ [CoFe-15Rod.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-15Rod.tdb): LIQUID, type code %, sha256 `b439f24ad16996c6…` ~~~~text 23: PHASE LIQUID:L % 1 1 ! 24: CONST LIQUID:L : CO FE : ! ~~~~ [CoFe-17Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-17Wan.tdb): LIQUID, type code %, sha256 `324b5028ec03d395…` ~~~~text 22: PHASE LIQUID:L % 1 1 ! 23: CONST LIQUID:L : CO FE : ! ~~~~ [CoFe-87Fer-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/CoFe-87Fer-LB.tdb): LIQUID, type code %, sha256 `edf9a6fc99f8e55a…` ~~~~text 21: PHASE LIQUID:L % 1 1 ! 22: CONST LIQUID:L : CO FE : ! ~~~~ Example references (3 of 3; assessments first): - [doi:10.1016/j.calphad.2015.03.001](https://doi.org/10.1016/j.calphad.2015.03.001) Justin E. Rodriguez, Douglas M. Matson, Thermodynamic modeling of the solidification path of levitated Fe–Co alloys, Calphad 49, 87-100 (2015). _assessment that models this phase_ - [doi:10.1016/j.calphad.2017.06.001](https://doi.org/10.1016/j.calphad.2017.06.001) J. Wang, X.-G. Lu, N. Zhu, W. Zheng, Calphad, 58, 82-100(2017). _assessment that models this phase_ - [doi:10.1016/S1359-6454(01)00337-8](https://doi.org/10.1016/S1359-6454%2801%2900337-8) I. Ohnuma, H. Enoki, O. Ikeda, R. Kainuma, H. Ohtani, B. Sundman, K. Ishida, Acta Mater., 50, 379-93(2002). _assessment that models this phase_ ## Please cite - R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735970 - R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23736065 Also cite B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work). Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes. ```bibtex @misc{orchid_phase_registry_2026, author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon}, title = {{ORCHID-Registry: phase registry of binary systems}}, version = {2026.10}, publisher = {Zenodo}, year = {2026}, doi = {10.5281/zenodo.23735970}, url = {https://doi.org/10.5281/zenodo.23735970}, note = {Version 1, machine-extracted} } @misc{orchid_data_2026, author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon}, title = {{ORCHID data: umbrella record of the ORCHID datasets}}, version = {2026.10}, publisher = {Zenodo}, year = {2026}, doi = {10.5281/zenodo.23736065}, url = {https://doi.org/10.5281/zenodo.23736065}, note = {Version 1, machine-extracted} } ``` --- Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite the ORCHID phase registry and the sources named on the page (TDB assessments, Hallstedt 2025, Materials Project, OQMD). TDB statements are quoted as written; parameter expressions are not reproduced. Field reference: [SCHEMA.md](https://data.orchid-project.org/phases/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt).