# B–Cu phases

> B–Cu system: 5 phases (tier A 3, liquid 1, needs_review 1); 3 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/B-CU.html · Markdown: https://data.orchid-project.org/phases/pages/B-CU.md

5 phases (tier A 3, liquid 1, needs_review 1); 3 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=B-CU) · [full JSON](https://data.orchid-project.org/phases/systems/B-CU.json) · [B–Cu system page](https://data.orchid-project.org/systems/B-CU.html) · [Markdown](https://data.orchid-project.org/phases/pages/B-CU.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the B–Cu system (5)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [BETA_RHOMBO_B](#phase-b-cu-b-beta-rhombo); _phase:b-cu:b-beta-rhombo_ |  | needs_review | stable in 2 of 2 calculated diagram(s): 300–3999.5 K, x(B) 0.96458–1 | 6 | 2 |
| [BCC_A2](#phase-b-cu-bcc-a2); _phase:b-cu:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | not stable in 2 calculated diagram(s) | 0 | 2 |
| [FCC_A1](#phase-b-cu-fcc-a1); _phase:b-cu:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 300–1357.77 K, x(B) 0–0.00357 | 6 | 2 |
| [HCP_A3](#phase-b-cu-hcp-a3); _phase:b-cu:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | not stable in 2 calculated diagram(s) | 0 | 2 |
| [LIQUID](#phase-b-cu-liquid); _phase:b-cu:liquid_ | liquid | liquid | stable in 2 of 2 calculated diagram(s): 1286.15–4000 K, x(B) 0–1 | 6 | 2 |

## BETA_RHOMBO_B (B–Cu)

- Id: `phase:b-cu:b-beta-rhombo`; status `needs_review`
- No structure assigned. Why: name_has_descriptive_tokens:RHOMBO; no_structure_token
- Candidate (sgte_mmc2): beta-B · hR105 · R-3m (166) — Hallstedt 2025 mmc2 row for BETA_RHOMBO_B: beta-B
- Candidate (tdb_comment): beta-B · hR105 · R-3m — CuB-09Wan.tdb: 'Prototype beta-B (hR105, R-3m)'
- Candidate (tdb_comment): beta-B · hR105 · R-3m — CuB-09Zha.tdb: 'Prototype beta-B (hR105, R-3m)'
- Stability: stable in 2 of 2 calculated diagram(s): 300–3999.5 K, x(B) 0.96458–1
- Literature: 6 values (6 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:b-cu:b-beta-rhombo)

Names (5): _corpus: _corpus:phase:b-cu:b-beta-rhombo, corpus:phase:b-cu:beta-rhombo-b  
_paper: _paper:10.1016/j.jallcom.2009.03.101:(B)  
_tdb: _tdb:CuB-09Wan.tdb:BETA_RHOMBO_B, tdb:CuB-09Zha.tdb:BETA_RHOMBO_B  


### TDB models of BETA_RHOMBO_B (2): PHASE and CONSTITUENT statements as written

[CuB-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Wan.tdb): BETA_RHOMBO_B, type code %, sha256 `ae21f67242115ca2…`

~~~~text
41: PHASE BETA_RHOMBO_B % 1 1 !
42: CONST BETA_RHOMBO_B : B% CU : !
~~~~

[CuB-09Zha.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Zha.tdb): BETA_RHOMBO_B, type code %, sha256 `bf22d31613d93de6…`

~~~~text
41: PHASE BETA_RHOMBO_B % 2 93 12 !
42: CONST BETA_RHOMBO_B : B : B CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1016/j.jallcom.2009.03.101](https://doi.org/10.1016/j.jallcom.2009.03.101) C.P. Wang, S.H. Guo, A.T. Tang, F.S. Pan, X.J. Liu, K. Ishida, Thermodynamic assessments of the Cu–B and Cu–Tm systems, Journal of Alloys and Compounds 482, 67-72 (2009).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1007/s11669-009-9561-7](https://doi.org/10.1007/s11669-009-9561-7) Wei-Wei Zhang, Yong Du, Honghui Xu, Wei Xiong, Yi Kong, Weihua Sun et al., Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations, J. Phase Equilib. Diffus. 30, 480-486 (2009).  
_assessment that models this phase_
- [doi:10.1016/0022-5088(65)90126-8](https://doi.org/10.1016/0022-5088%2865%2990126-8) Fritz Wald, Richard W. Stormont, Investigations on the constitution of certain binary boron-metal systems, Journal of the Less Common Metals 9, 423-433 (1965).  
_cited as the source of values for this phase_

## BCC_A2 (B–Cu)

- Id: `phase:b-cu:bcc-a2`; status `assigned`
- Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high
- Stability: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:b-cu:bcc-a2)

Names (3): _corpus: _corpus:phase:b-cu:bcc-a2  
_tdb: _tdb:CuB-09Wan.tdb:BCC_A2, tdb:CuB-09Zha.tdb:BCC_A2  


### TDB models of BCC_A2 (2): PHASE and CONSTITUENT statements as written

[CuB-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Wan.tdb): BCC_A2, type code %B, sha256 `ae21f67242115ca2…`

~~~~text
31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : CU : VA : !
~~~~

[CuB-09Zha.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Zha.tdb): BCC_A2, type code %B, sha256 `bf22d31613d93de6…`

~~~~text
31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : CU : B VA% : !
~~~~

Example references (2 of 2; assessments first): 

- [doi:10.1007/s11669-009-9561-7](https://doi.org/10.1007/s11669-009-9561-7) Wei-Wei Zhang, Yong Du, Honghui Xu, Wei Xiong, Yi Kong, Weihua Sun et al., Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations, J. Phase Equilib. Diffus. 30, 480-486 (2009).  
_assessment that models this phase_
- [doi:10.1016/j.jallcom.2009.03.101](https://doi.org/10.1016/j.jallcom.2009.03.101) C.P. Wang, S.H. Guo, A.T. Tang, F.S. Pan, X.J. Liu, K. Ishida, Thermodynamic assessments of the Cu–B and Cu–Tm systems, Journal of Alloys and Compounds 482, 67-72 (2009).  
_assessment that models this phase_

## FCC_A1 (B–Cu)

- Id: `phase:b-cu: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 2 of 2 calculated diagram(s): 300–1357.77 K, x(B) 0–0.00357
- Literature: 6 values (6 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:b-cu:fcc-a1)

Names (4): _corpus: _corpus:phase:b-cu:fcc-a1  
_paper: _paper:10.1016/j.jallcom.2009.03.101:(Cu)  
_tdb: _tdb:CuB-09Wan.tdb:FCC_A1, tdb:CuB-09Zha.tdb:FCC_A1  


### TDB models of FCC_A1 (2): PHASE and CONSTITUENT statements as written

[CuB-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Wan.tdb): FCC_A1, type code %A, sha256 `ae21f67242115ca2…`

~~~~text
26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : B CU% : VA : !
~~~~

[CuB-09Zha.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Zha.tdb): FCC_A1, type code %A, sha256 `bf22d31613d93de6…`

~~~~text
26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : CU : B VA% : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1016/j.jallcom.2009.03.101](https://doi.org/10.1016/j.jallcom.2009.03.101) C.P. Wang, S.H. Guo, A.T. Tang, F.S. Pan, X.J. Liu, K. Ishida, Thermodynamic assessments of the Cu–B and Cu–Tm systems, Journal of Alloys and Compounds 482, 67-72 (2009).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1007/s11669-009-9561-7](https://doi.org/10.1007/s11669-009-9561-7) Wei-Wei Zhang, Yong Du, Honghui Xu, Wei Xiong, Yi Kong, Weihua Sun et al., Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations, J. Phase Equilib. Diffus. 30, 480-486 (2009).  
_assessment that models this phase_
- [doi:10.1016/0022-5088(65)90126-8](https://doi.org/10.1016/0022-5088%2865%2990126-8) Fritz Wald, Richard W. Stormont, Investigations on the constitution of certain binary boron-metal systems, Journal of the Less Common Metals 9, 423-433 (1965).  
_cited as the source of values for this phase_

## HCP_A3 (B–Cu)

- Id: `phase:b-cu: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: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:b-cu:hcp-a3)

Names (3): _corpus: _corpus:phase:b-cu:hcp-a3  
_tdb: _tdb:CuB-09Wan.tdb:HCP_A3, tdb:CuB-09Zha.tdb:HCP_A3  


### TDB models of HCP_A3 (2): PHASE and CONSTITUENT statements as written

[CuB-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Wan.tdb): HCP_A3, type code %A, sha256 `ae21f67242115ca2…`

~~~~text
36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : CU : VA : !
~~~~

[CuB-09Zha.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Zha.tdb): HCP_A3, type code %A, sha256 `bf22d31613d93de6…`

~~~~text
36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : CU : B VA% : !
~~~~

Example references (2 of 2; assessments first): 

- [doi:10.1007/s11669-009-9561-7](https://doi.org/10.1007/s11669-009-9561-7) Wei-Wei Zhang, Yong Du, Honghui Xu, Wei Xiong, Yi Kong, Weihua Sun et al., Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations, J. Phase Equilib. Diffus. 30, 480-486 (2009).  
_assessment that models this phase_
- [doi:10.1016/j.jallcom.2009.03.101](https://doi.org/10.1016/j.jallcom.2009.03.101) C.P. Wang, S.H. Guo, A.T. Tang, F.S. Pan, X.J. Liu, K. Ishida, Thermodynamic assessments of the Cu–B and Cu–Tm systems, Journal of Alloys and Compounds 482, 67-72 (2009).  
_assessment that models this phase_

## LIQUID (B–Cu)

- Id: `phase:b-cu:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 2 of 2 calculated diagram(s): 1286.15–4000 K, x(B) 0–1
- Literature: 6 values (6 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:b-cu:liquid)

Names (4): _corpus: _corpus:phase:b-cu:liquid  
_paper: _paper:10.1016/j.jallcom.2009.03.101:L  
_tdb: _tdb:CuB-09Wan.tdb:LIQUID, tdb:CuB-09Zha.tdb:LIQUID  


### TDB models of LIQUID (2): PHASE and CONSTITUENT statements as written

[CuB-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Wan.tdb): LIQUID, type code %, sha256 `ae21f67242115ca2…`

~~~~text
21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : B CU : !
~~~~

[CuB-09Zha.tdb](https://orchid-project.org/data/databases/sgte-binary/CuB-09Zha.tdb): LIQUID, type code %, sha256 `bf22d31613d93de6…`

~~~~text
21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : B CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1016/j.jallcom.2009.03.101](https://doi.org/10.1016/j.jallcom.2009.03.101) C.P. Wang, S.H. Guo, A.T. Tang, F.S. Pan, X.J. Liu, K. Ishida, Thermodynamic assessments of the Cu–B and Cu–Tm systems, Journal of Alloys and Compounds 482, 67-72 (2009).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1007/s11669-009-9561-7](https://doi.org/10.1007/s11669-009-9561-7) Wei-Wei Zhang, Yong Du, Honghui Xu, Wei Xiong, Yi Kong, Weihua Sun et al., Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations, J. Phase Equilib. Diffus. 30, 480-486 (2009).  
_assessment that models this phase_
- [doi:10.1016/0022-5088(65)90126-8](https://doi.org/10.1016/0022-5088%2865%2990126-8) Fritz Wald, Richard W. Stormont, Investigations on the constitution of certain binary boron-metal systems, Journal of the Less Common Metals 9, 423-433 (1965).  
_cited as the source of values for 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).