# Al–Cu phases

> Al–Cu system: 23 phases (tier A 8, tier C 5, liquid 1, needs_review 9); 22 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/AL-CU.html · Markdown: https://data.orchid-project.org/phases/pages/AL-CU.md

23 phases (tier A 8, tier C 5, liquid 1, needs_review 9); 22 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=AL-CU) · [full JSON](https://data.orchid-project.org/phases/systems/AL-CU.json) · [Al–Cu system page](https://data.orchid-project.org/systems/AL-CU.html) · [Markdown](https://data.orchid-project.org/phases/pages/AL-CU.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the Al–Cu system (23)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [AL2CU_C16](#phase-al-cu-al2cu-c16); _phase:al-cu:al2cu-c16_ | Al2Cu · C16 · tI12 · I4/mcm (140) | tier A: standard phase name | stable in 4 of 4 calculated diagram(s): 300–869.01 K, x(Cu) 0.31631–0.3367 | 12 | 4 |
| [AL2CU_PRIME](#phase-al-cu-al2cu-prime); _phase:al-cu:al2cu-prime_ |  | needs_review | not stable in 2 calculated diagram(s) | 0 | 2 |
| [AL2CU3](#phase-al-cu-al2cu3); _phase:al-cu:al2cu3_ | Al5Cu8 · hR52 · R3m (160) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 2 of 2 calculated diagram(s): 300–959.78 K, x(Cu) 0.6–0.6 | 0 | 2 |
| [AL3CU4_HT](#phase-al-cu-al3cu4-ht); _phase:al-cu:al3cu4-ht_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 645.25–854.09 K, x(Cu) 0.561–0.561 | 6 | 1 |
| [AL3CU4_LT](#phase-al-cu-al3cu4-lt); _phase:al-cu:al3cu4-lt_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–833.46 K, x(Cu) 0.573–0.573 | 0 | 1 |
| [AL4CU9_D82](#phase-al-cu-al4cu9-d82); _phase:al-cu:al4cu9-d82_ | Cu5Zn8 · D8_2 · cI52 · I-43m (217) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 1054.21–1293.41 K, x(Cu) 0.65575–0.68881 | 0 | 2 |
| [AL4CU9_D83](#phase-al-cu-al4cu9-d83); _phase:al-cu:al4cu9-d83_ | Al4Cu9 · D8_3 · cP52 · P-43m (215) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 300–1150.5 K, x(Cu) 0.62135–0.69231 | 0 | 2 |
| [AL4CU9_GAMMA](#phase-al-cu-al4cu9-gamma); _phase:al-cu:al4cu9-gamma_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–1293.77 K, x(Cu) 0.61724–0.70148 | 11 | 1 |
| [AL5CU8](#phase-al-cu-al5cu8); _phase:al-cu:al5cu8_ | Al5Cu8 · hR52 · R3m (160) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 2 of 2 calculated diagram(s): 300–960 K, x(Cu) 0.59596–0.61545 | 9 | 2 |
| [AL9CU11](#phase-al-cu-al9cu11); _phase:al-cu:al9cu11_ |  | needs_review | stable in 3 of 3 calculated diagram(s): 300–874.57 K, x(Cu) 0.55–0.5574 | 0 | 3 |
| [ALCU_ETA_1](#phase-al-cu-alcu-1-eta); _phase:al-cu:alcu-1-eta_ | AlCu(h) · oC32 · Cmmm (65) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 846.87–898.18 K, x(Cu) 0.50891–0.51225 | 0 | 1 |
| [ALCU_ETA_2](#phase-al-cu-alcu-2-eta); _phase:al-cu:alcu-2-eta_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–871.03 K, x(Cu) 0.52–0.52 | 0 | 1 |
| [ALCU_B82](#phase-al-cu-alcu-b82); _phase:al-cu:alcu-b82_ |  | needs_review | stable in 4 of 4 calculated diagram(s): 830.82–1124.24 K, x(Cu) 0.5403–0.60043 | 28 | 4 |
| [ALCU_ETA](#phase-al-cu-alcu-eta); _phase:al-cu:alcu-eta_ |  | needs_review | stable in 2 of 2 calculated diagram(s): 300–898.11 K, x(Cu) 0.5–0.51097 | 0 | 2 |
| [ALCU_ETA_HT](#phase-al-cu-alcu-eta-ht); _phase:al-cu:alcu-eta-ht_ | AlCu(h) · oC32 · Cmmm (65) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 846.77–897.67 K, x(Cu) 0.51175–0.5165 | 17 | 1 |
| [ALCU_ETA_LT](#phase-al-cu-alcu-eta-lt); _phase:al-cu:alcu-eta-lt_ | AlCu(r) · mC20 · C2/m (12) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 300–871.89 K, x(Cu) 0.5–0.53158 | 11 | 1 |
| [ALCU3_D022](#phase-al-cu-alcu3-d022); _phase:al-cu:alcu3-d022_ |  | needs_review | stable in 2 of 2 calculated diagram(s): 300–640 K, x(Cu) 0.77–0.77 | 0 | 2 |
| [BCC_A2](#phase-al-cu-bcc-a2); _phase:al-cu:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 5 of 5 calculated diagram(s): 300–1329.45 K, x(Cu) 0.32085–0.81606 | 38 | 5 |
| [GAMMA_D82](#phase-al-cu-d82-gamma); _phase:al-cu:d82-gamma_ | Cu5Zn8 · D8_2 · cI52 · I-43m (217) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 1050.72–1286.31 K, x(Cu) 0.64361–0.69815 | 16 | 2 |
| [GAMMA_D83](#phase-al-cu-d83-gamma); _phase:al-cu:d83-gamma_ | Al4Cu9 · D8_3 · cP52 · P-43m (215) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 300–1145.67 K, x(Cu) 0.62085–0.69906 | 20 | 2 |
| [FCC_A1](#phase-al-cu-fcc-a1); _phase:al-cu:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 5 of 5 calculated diagram(s): 300–1358.62 K, x(Cu) 0–1 | 16 | 5 |
| [HCP_A3](#phase-al-cu-hcp-a3); _phase:al-cu:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 5 calculated diagram(s): 747.05–1015.23 K, x(Cu) 0.26592–0.37287 | 0 | 5 |
| [LIQUID](#phase-al-cu-liquid); _phase:al-cu:liquid_ | liquid | liquid | stable in 5 of 5 calculated diagram(s): 820.61–2500 K, x(Cu) 0–1 | 42 | 5 |

## AL2CU_C16 (Al–Cu)

- Id: `phase:al-cu:al2cu-c16`; status `assigned`
- Structure: Al2Cu · C16 · tI12 · I4/mcm (140); type `st:c16-al2cu-ti12`; tier A: standard phase name; confidence high
- Caveat: partitioned order/disorder model in AlCu-21Kro.tdb also describes the disordered state
- Stability: stable in 4 of 4 calculated diagram(s): 300–869.01 K, x(Cu) 0.31631–0.3367
- Literature: 12 values (10 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al2cu-c16)

Names (6): _corpus: _corpus:phase:al-cu:al2cu-c16  
_paper: _paper:10.1007/s10853-020-05423-7:θ  
_tdb: _tdb:AlCu-04Wit.tdb:AL2CU_C16, tdb:AlCu-15Lia.tdb:AL2CU_C16, tdb:AlCu-21Kro.tdb:AL2CU_C16, tdb:AlCu-98Sau-LB.tdb:AL2CU_C16  


### TDB models of AL2CU_C16 (4): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL2CU_C16, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
60: PHASE AL2CU_C16 % 2 2 1 !
61: CONST AL2CU_C16 : AL : AL CU% : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): AL2CU_C16, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
50: PHASE AL2CU_C16 % 2 2 1 !
51: CONST AL2CU_C16 : AL : AL CU% : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): AL2CU_C16, type code %, sha256 `bd06016e51db2bef…`

~~~~text
45: PHASE AL2CU_C16 % 2 2 1 !
46: CONST AL2CU_C16 : AL% CU : AL CU% : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL2CU_C16, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
57: PHASE AL2CU_C16 % 2 2 1 !
58: CONST AL2CU_C16 : AL : AL CU% : !
~~~~

Example references (4 of 4; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## AL2CU_PRIME (Al–Cu)

- Id: `phase:al-cu:al2cu-prime`; status `needs_review`
- No structure assigned. Why: assessment_declared_conflicts_with_dft; name_has_descriptive_tokens:PRIME; no_structure_token
- Candidate (dft_mp): Fm-3m (225) — on-hull MP Al2Cu at x(CU)=0.3333
- Candidate (dft_oqmd): Fm-3m (225) — on-hull OQMD Al2 Cu1 at x(CU)=0.3333
- Candidate (sgte_mmc2): Al2Cu · oF24 · Fmmm (69) — Hallstedt 2025 mmc2 row for AL2CU_PRIME: Al2Cu (theta-prime, metastable)
- Candidate (tdb_comment): Al2Cu · oF24 · Fmmm — AlCu-04Wit.tdb: 'Prototype Al2Cu (oF24, Fmmm)'
- Candidate (tdb_comment): Al2Cu · oF24 · Fmmm — AlCu-98Sau-LB.tdb: 'Prototype Al2Cu (oF24, Fmmm)'
- Stoichiometry: Al 0.6667, Cu 0.3333
- 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:al-cu:al2cu-prime)

Names (3): _corpus: _corpus:phase:al-cu:al2cu-prime  
_tdb: _tdb:AlCu-04Wit.tdb:AL2CU_PRIME, tdb:AlCu-98Sau-LB.tdb:AL2CU_PRIME  


### TDB models of AL2CU_PRIME (2): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL2CU_PRIME, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
66: PHASE AL2CU_PRIME % 2 2 1 !
67: CONST AL2CU_PRIME : AL : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL2CU_PRIME, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
63: PHASE AL2CU_PRIME % 2 2 1 !
64: CONST AL2CU_PRIME : AL : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## AL2CU3 (Al–Cu)

- Id: `phase:al-cu:al2cu3`; status `assigned`
- Structure: Al5Cu8 · hR52 · R3m (160); type `st:al5cu8-hr52`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stoichiometry: Al 0.4000, Cu 0.6000
- Stability: stable in 2 of 2 calculated diagram(s): 300–959.78 K, x(Cu) 0.6–0.6
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al2cu3)

Names (3): _corpus: _corpus:phase:al-cu:al2cu3  
_tdb: _tdb:AlCu-04Wit.tdb:AL2CU3, tdb:AlCu-98Sau-LB.tdb:AL2CU3  


### TDB models of AL2CU3 (2): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL2CU3, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
89: PHASE AL2CU3 % 2 2 3 !
90: CONST AL2CU3 : AL : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL2CU3, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
86: PHASE AL2CU3 % 2 2 3 !
87: CONST AL2CU3 : AL : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## AL3CU4_HT (Al–Cu)

- Id: `phase:al-cu:al3cu4-ht`; status `needs_review`
- No structure assigned. Why: assessment_declared_compound_differs_from_model_composition; no_on_hull_entry_in_both; no_structure_token
- Candidate (literature_printed): Al3Cu4(h) · oF88 — printed with a label mapped to this phase
- Candidate (sgte_mmc2): Al3Cu4(h) · oF88 · Fmm2 (42) — Hallstedt 2025 mmc2 row for AL3CU4_HT: Al3Cu4 (zeta-1, high T)
- Candidate (tdb_comment): Al3Cu4(h) · oF88 · Fmm2 — AlCu-21Kro.tdb: 'Prototype Al3Cu4(h) (oF88, Fmm2), Al9Cu11(h), zeta-1, high T'
- Stoichiometry: Al 0.4390, Cu 0.5610
- Stability: stable in 1 of 1 calculated diagram(s): 645.25–854.09 K, x(Cu) 0.561–0.561
- Literature: 6 values (6 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al3cu4-ht)

Names (3): _corpus: _corpus:phase:al-cu:al3cu4-ht  
_paper: _paper:10.1007/s10853-020-05423-7:ζ  
_tdb: _tdb:AlCu-21Kro.tdb:AL3CU4_HT  


### TDB models of AL3CU4_HT (1): PHASE and CONSTITUENT statements as written

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): AL3CU4_HT, type code %, sha256 `bd06016e51db2bef…`

~~~~text
66: PHASE AL3CU4_HT % 2 0.439 0.561 !
67: CONST AL3CU4_HT : AL : CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## AL3CU4_LT (Al–Cu)

- Id: `phase:al-cu:al3cu4-lt`; status `needs_review`
- No structure assigned. Why: assessment_declared_compound_differs_from_site_ratios; no_structure_token; off_stoichiometric_model
- Candidate (sgte_mmc2): Al3Cu4(r) · oI24 · Imm2 (44) — Hallstedt 2025 mmc2 row for AL3CU4_LT: Al3Cu4 (zeta-2, low T)
- Candidate (tdb_comment): Al3Cu4(r) · oI24 · Imm2 — AlCu-21Kro.tdb: 'Prototype Al3Cu4(r) (oI24, Imm2), Al9Cu11(r), zeta-2/prime, low T'
- Stability: stable in 1 of 1 calculated diagram(s): 300–833.46 K, x(Cu) 0.573–0.573
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al3cu4-lt)

Names (2): _corpus: _corpus:phase:al-cu:al3cu4-lt  
_tdb: _tdb:AlCu-21Kro.tdb:AL3CU4_LT  


### TDB models of AL3CU4_LT (1): PHASE and CONSTITUENT statements as written

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): AL3CU4_LT, type code %, sha256 `bd06016e51db2bef…`

~~~~text
61: PHASE AL3CU4_LT % 2 0.427 0.573 !
62: CONST AL3CU4_LT : AL% CU : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase_

## AL4CU9_D82 (Al–Cu)

- Id: `phase:al-cu:al4cu9-d82`; status `assigned`
- Structure: Cu5Zn8 · D8_2 · cI52 · I-43m (217); type `st:d8-2-cu5zn8-ci52`; tier A: standard phase name; confidence high
- Stability: stable in 2 of 2 calculated diagram(s): 1054.21–1293.41 K, x(Cu) 0.65575–0.68881
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al4cu9-d82)

Names (3): _corpus: _corpus:phase:al-cu:al4cu9-d82  
_tdb: _tdb:AlCu-04Wit.tdb:AL4CU9_D82, tdb:AlCu-98Sau-LB.tdb:AL4CU9_D82  


### TDB models of AL4CU9_D82 (2): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL4CU9_D82, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
99: PHASE AL4CU9_D82 % 3 4 1 8 !
100: CONST AL4CU9_D82 : AL : AL CU% : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL4CU9_D82, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
96: PHASE AL4CU9_D82 % 3 4 1 8 !
97: CONST AL4CU9_D82 : AL : AL CU% : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## AL4CU9_D83 (Al–Cu)

- Id: `phase:al-cu:al4cu9-d83`; status `assigned`
- Structure: Al4Cu9 · D8_3 · cP52 · P-43m (215); type `st:d8-3-al4cu9-cp52`; tier A: standard phase name; confidence high
- Stability: stable in 2 of 2 calculated diagram(s): 300–1150.5 K, x(Cu) 0.62135–0.69231
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al4cu9-d83)

Names (3): _corpus: _corpus:phase:al-cu:al4cu9-d83  
_tdb: _tdb:AlCu-04Wit.tdb:AL4CU9_D83, tdb:AlCu-98Sau-LB.tdb:AL4CU9_D83  


### TDB models of AL4CU9_D83 (2): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL4CU9_D83, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
94: PHASE AL4CU9_D83 % 3 4 1 8 !
95: CONST AL4CU9_D83 : AL : AL CU% : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL4CU9_D83, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
91: PHASE AL4CU9_D83 % 3 4 1 8 !
92: CONST AL4CU9_D83 : AL : AL CU% : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## AL4CU9_GAMMA (Al–Cu)

- Id: `phase:al-cu:al4cu9-gamma`; status `needs_review`
- No structure assigned. Why: no_structure_token; off_stoichiometric_model; sgte_mmc2_rows_disagree
- Candidate (dft_mp): P-43m (215) — on-hull MP Al4Cu9 at x(CU)=0.6923
- Candidate (dft_oqmd): P-43m (215) — on-hull OQMD Al4 Cu9 at x(CU)=0.6923
- Candidate (literature_printed): Al4Cu9 · cP52 — printed with a label mapped to this phase
- Candidate (sgte_mmc2): Cu5Zn8 · D8_2 · cI52 · I-43m (217) — Hallstedt 2025 mmc2 row for AL4CU9_GAMMA: Al4Cu9 (gamma-0, gamma-2, high T)
- Candidate (sgte_mmc2): Al4Cu9 · D8_3 · cP52 · P-43m (215) — Hallstedt 2025 mmc2 row for AL4CU9_GAMMA: Al4Cu9 (gamma-1, low-T)
- Candidate (tdb_comment): Al4Cu9 · cP52 · P-43m — AlCu-02Mie.tdb: 'Prototype Al4Cu9 (cP52, P-43m) gamma-1'
- Candidate (tdb_comment): Cu5Zn8 · cI52 · I-43m — AlCu-02Mie.tdb: 'Prototype Cu5Zn8 (cI52, I-43m) gamma-0'
- Stability: stable in 1 of 1 calculated diagram(s): 300–1293.77 K, x(Cu) 0.61724–0.70148
- Literature: 11 values (11 accepted) from 2 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al4cu9-gamma)

Names (4): _corpus: _corpus:phase:al-cu:al4cu9-gamma  
_paper: _paper:10.1007/s11661-002-0173-7:γ, paper:sha256-85fd53a1a176b694:AlCu-γ(D83)  
_tdb: _tdb:AlCu-02Mie.tdb:AL4CU9_GAMMA  


### TDB models of AL4CU9_GAMMA (1): PHASE and CONSTITUENT statements as written

[AlCu-02Mie.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-02Mie.tdb): AL4CU9_GAMMA, type code %, sha256 `3831fc8d892fc077…`

~~~~text
44: PHASE AL4CU9_GAMMA % 1 1 !
45: CONST AL4CU9_GAMMA : AL CU : !
~~~~

Example references (2 of 2; assessments first): 

- [doi:10.1007/s11661-002-0173-7](https://doi.org/10.1007/s11661-002-0173-7) J. Miettinen, Thermodynamic description of the Cu-Al-Sn system in the copper-rich corner, Metall Mater Trans A 33, 1639-1648 (2002).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1179/imr.1985.30.1.211](https://doi.org/10.1179/imr.1985.30.1.211) J. L. Murray, The aluminium-copper system, International Materials Reviews 30, 211-234 (1985).  
_cited as the source of values for this phase_

## AL5CU8 (Al–Cu)

- Id: `phase:al-cu:al5cu8`; status `assigned`
- Structure: Al5Cu8 · hR52 · R3m (160); type `st:al5cu8-hr52`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 2 of 2 calculated diagram(s): 300–960 K, x(Cu) 0.59596–0.61545
- Literature: 9 values (9 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al5cu8)

Names (4): _corpus: _corpus:phase:al-cu:al5cu8  
_paper: _paper:10.1007/s10853-020-05423-7:δ  
_tdb: _tdb:AlCu-15Lia.tdb:AL5CU8, tdb:AlCu-21Kro.tdb:AL5CU8  


### TDB models of AL5CU8 (2): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): AL5CU8, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
77: PHASE AL5CU8 % 2 5 8 !
78: CONST AL5CU8 : AL : CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): AL5CU8, type code %, sha256 `bd06016e51db2bef…`

~~~~text
77: PHASE AL5CU8 % 2 5 8 !
78: CONST AL5CU8 : AL% CU : AL CU% : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## AL9CU11 (Al–Cu)

- Id: `phase:al-cu:al9cu11`; status `needs_review`
- No structure assigned. Why: no_structure_token; off_stoichiometric_model; sgte_mmc2_rows_disagree
- Candidate (sgte_mmc2): Al3Cu4(h) · oF88 · Fmm2 (42) — Hallstedt 2025 mmc2 row for AL9CU11: Al9Cu11 (zeta-1, high T)
- Candidate (sgte_mmc2): Al3Cu4(r) · oI24 · Imm2 (44) — Hallstedt 2025 mmc2 row for AL9CU11: Al9Cu11 (zeta-2, low T)
- Candidate (tdb_comment): Al9Cu11(h) · oF88 · Fmm2 — AlCu-04Wit.tdb: 'Prototype Al9Cu11(h) (oF88, Fmm2), zeta-1, high T'
- Candidate (tdb_comment): Al9Cu11(r) · oI24 · Imm2 — AlCu-04Wit.tdb: 'Prototype Al9Cu11(r) (oI24, Imm2), zeta-2, low T'
- Candidate (tdb_comment): Al9Cu11(h) · oF88 · Fmm2 — AlCu-15Lia.tdb: 'Prototype Al9Cu11(h) (oF88, Fmm2), zeta-1, high T'
- Candidate (tdb_comment): Al9Cu11(r) · oI24 · Imm2 — AlCu-15Lia.tdb: 'Prototype Al9Cu11(r) (oI24, Imm2), zeta-2, low T'
- Candidate (tdb_comment): Al9Cu11(h) · oF88 · Fmm2 — AlCu-98Sau-LB.tdb: 'Prototype Al9Cu11(h) (oF88, Fmm2), zeta-1, high T'
- Candidate (tdb_comment): Al9Cu11(r) · oI24 · Imm2 — AlCu-98Sau-LB.tdb: 'Prototype Al9Cu11(r) (oI24, Imm2), zeta-2, low T'
- Stability: stable in 3 of 3 calculated diagram(s): 300–874.57 K, x(Cu) 0.55–0.5574
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:al9cu11)

Names (4): _corpus: _corpus:phase:al-cu:al9cu11  
_tdb: _tdb:AlCu-04Wit.tdb:AL9CU11, tdb:AlCu-15Lia.tdb:AL9CU11, tdb:AlCu-98Sau-LB.tdb:AL9CU11  


### TDB models of AL9CU11 (3): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): AL9CU11, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
78: PHASE AL9CU11 % 2 9 11 !
79: CONST AL9CU11 : AL : CU : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): AL9CU11, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
66: PHASE AL9CU11 % 2 9 11 !
67: CONST AL9CU11 : AL% CU : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): AL9CU11, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
75: PHASE AL9CU11 % 2 9 11 !
76: CONST AL9CU11 : AL : CU : !
~~~~

Example references (2 of 2; assessments first): 

- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## ALCU_ETA_1 (Al–Cu)

- Id: `phase:al-cu:alcu-1-eta`; status `assigned`
- Structure: AlCu(h) · oC32 · Cmmm (65); type `st:alcu-h-oc32`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (name_has_descriptive_tokens:1, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 1 of 1 calculated diagram(s): 846.87–898.18 K, x(Cu) 0.50891–0.51225
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-1-eta)

Names (2): _corpus: _corpus:phase:al-cu:alcu-1-eta  
_tdb: _tdb:AlCu-15Lia.tdb:ALCU_ETA_1  


### TDB models of ALCU_ETA_1 (1): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): ALCU_ETA_1, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
55: PHASE ALCU_ETA_1 % 2 1 1 !
56: CONST ALCU_ETA_1 : AL% CU : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase_

## ALCU_ETA_2 (Al–Cu)

- Id: `phase:al-cu:alcu-2-eta`; status `needs_review`
- No structure assigned. Why: assessment_declared_compound_differs_from_model_composition; name_has_descriptive_tokens:2; no_structure_token
- Candidate (sgte_mmc2): AlCu(r) · mC20 · C2/m (12) — Hallstedt 2025 mmc2 row for ALCU_ETA_2: AlCu (eta-2, low T)
- Candidate (tdb_comment): AlCu(r) · mC20 · C2/m — AlCu-15Lia.tdb: 'Prototype AlCu(r) (mC20, C2/m), low T'
- Stoichiometry: Al 0.4800, Cu 0.5200
- Stability: stable in 1 of 1 calculated diagram(s): 300–871.03 K, x(Cu) 0.52–0.52
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-2-eta)

Names (2): _corpus: _corpus:phase:al-cu:alcu-2-eta  
_tdb: _tdb:AlCu-15Lia.tdb:ALCU_ETA_2  


### TDB models of ALCU_ETA_2 (1): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): ALCU_ETA_2, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
60: PHASE ALCU_ETA_2 % 2 0.48 0.52 !
61: CONST ALCU_ETA_2 : AL : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase_

## ALCU_B82 (Al–Cu)

- Id: `phase:al-cu:alcu-b82`; status `needs_review`
- No structure assigned. Why: site_ratios_contradict_B8_2:AlCu-04Wit.tdb; site_ratios_contradict_B8_2:AlCu-15Lia.tdb; site_ratios_contradict_B8_2:AlCu-21Kro.tdb; site_ratios_contradict_B8_2:AlCu-98Sau-LB.tdb
- Candidate (dft_oqmd): C2/m (12) — on-hull OQMD Al9 Cu13 at x(CU)=0.5909
- Candidate (name_token): InNi2 · B8_2 · hP6 · P6_3/mmc (194) — Strukturbericht/word 'B82' in the TDB name
- Candidate (sgte_mmc2): InNi2 · B8_2 · hP6 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for ALCU_B82: AlCu-epsilon-2 (Al2Cu3)
- Candidate (tdb_comment): InNi2 · hP6 · P6_3/mmc — AlCu-04Wit.tdb: 'Prototype InNi2 (hP6, P6_3/mmc), epsilon-2'
- Candidate (tdb_comment): InNi2 · hP6 · P6_3/mmc — AlCu-15Lia.tdb: 'Prototype InNi2 (hP6, P6_3/mmc), epsilon-2'
- Candidate (tdb_comment): InNi2 · hP6 · P6_3/mmc — AlCu-21Kro.tdb: 'Prototype InNi2 (hP6, P6_3/mmc), epsilon-2/prime'
- Candidate (tdb_comment): InNi2 · hP6 · P6_3/mmc — AlCu-98Sau-LB.tdb: 'Prototype InNi2 (hP6, P6_3/mmc), epsilon-2'
- Stability: stable in 4 of 4 calculated diagram(s): 830.82–1124.24 K, x(Cu) 0.5403–0.60043
- Literature: 28 values (28 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-b82)

Names (6): _corpus: _corpus:phase:al-cu:alcu-b82  
_paper: _paper:10.1007/s10853-020-05423-7:ε′  
_tdb: _tdb:AlCu-04Wit.tdb:ALCU_B82, tdb:AlCu-15Lia.tdb:ALCU_B82, tdb:AlCu-21Kro.tdb:ALCU_B82, tdb:AlCu-98Sau-LB.tdb:ALCU_B82  


### TDB models of ALCU_B82 (4): PHASE and CONSTITUENT statements as written

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): ALCU_B82, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
83: PHASE ALCU_B82 % 2 1 1 !
84: CONST ALCU_B82 : AL% CU : CU : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): ALCU_B82, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
71: PHASE ALCU_B82 % 2 1 1 !
72: CONST ALCU_B82 : AL% CU : CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): ALCU_B82, type code %, sha256 `bd06016e51db2bef…`

~~~~text
71: PHASE ALCU_B82 % 2 1 1 !
72: CONST ALCU_B82 : AL% CU : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): ALCU_B82, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
80: PHASE ALCU_B82 % 2 1 1 !
81: CONST ALCU_B82 : AL% CU : CU : !
~~~~

Example references (4 of 4; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## ALCU_ETA (Al–Cu)

- Id: `phase:al-cu:alcu-eta`; status `needs_review`
- No structure assigned. Why: no_structure_token; off_stoichiometric_model; sgte_mmc2_rows_disagree
- Candidate (dft_mp): C2/m (12) — on-hull MP AlCu at x(CU)=0.5000
- Candidate (dft_oqmd): P-1 (2) — on-hull OQMD Al1 Cu1 at x(CU)=0.5000
- Candidate (sgte_mmc2): AlCu(h) · oC32 · Cmmm (65) — Hallstedt 2025 mmc2 row for ALCU_ETA: AlCu (eta-1, high T)
- Candidate (sgte_mmc2): AlCu(r) · mC20 · C2/m (12) — Hallstedt 2025 mmc2 row for ALCU_ETA: AlCu (eta-2, low T)
- Candidate (tdb_comment): AlCu(h) · oC32 · Cmmm — AlCu-04Wit.tdb: 'Prototype AlCu(h) (oC32, Cmmm), eta-1, high T'
- Candidate (tdb_comment): AlCu(r) · mC20 · C2/m — AlCu-04Wit.tdb: 'Prototype AlCu(r) (mC20, C2/m), eta-2, low T'
- Candidate (tdb_comment): AlCu(h) · oC32 · Cmmm — AlCu-98Sau-LB.tdb: 'Prototype AlCu(h) (oC32, Cmmm), eta-1, high T'
- Candidate (tdb_comment): AlCu(r) · mC20 · C2/m — AlCu-98Sau-LB.tdb: 'Prototype AlCu(r) (mC20, C2/m), eta-2, low T'
- Stability: stable in 2 of 2 calculated diagram(s): 300–898.11 K, x(Cu) 0.5–0.51097
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-eta)

Names (3): _corpus: _corpus:phase:al-cu:alcu-eta  
_tdb: _tdb:AlCu-04Wit.tdb:ALCU_ETA, tdb:AlCu-98Sau-LB.tdb:ALCU_ETA  


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

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): ALCU_ETA, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
72: PHASE ALCU_ETA % 2 1 1 !
73: CONST ALCU_ETA : AL% CU : CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): ALCU_ETA, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
69: PHASE ALCU_ETA % 2 1 1 !
70: CONST ALCU_ETA : AL% CU : CU : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## ALCU_ETA_HT (Al–Cu)

- Id: `phase:al-cu:alcu-eta-ht`; status `assigned`
- Structure: AlCu(h) · oC32 · Cmmm (65); type `st:alcu-h-oc32`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 1 of 1 calculated diagram(s): 846.77–897.67 K, x(Cu) 0.51175–0.5165
- Literature: 17 values (15 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-eta-ht)

Names (3): _corpus: _corpus:phase:al-cu:alcu-eta-ht  
_paper: _paper:10.1007/s10853-020-05423-7:η  
_tdb: _tdb:AlCu-21Kro.tdb:ALCU_ETA_HT  


### TDB models of ALCU_ETA_HT (1): PHASE and CONSTITUENT statements as written

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): ALCU_ETA_HT, type code %, sha256 `bd06016e51db2bef…`

~~~~text
56: PHASE ALCU_ETA_HT % 2 1 1 !
57: CONST ALCU_ETA_HT : AL% CU : CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## ALCU_ETA_LT (Al–Cu)

- Id: `phase:al-cu:alcu-eta-lt`; status `assigned`
- Structure: AlCu(r) · mC20 · C2/m (12); type `st:alcu-r-mc20`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
- Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 1 of 1 calculated diagram(s): 300–871.89 K, x(Cu) 0.5–0.53158
- Literature: 11 values (9 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu-eta-lt)

Names (3): _corpus: _corpus:phase:al-cu:alcu-eta-lt  
_paper: _paper:10.1007/s10853-020-05423-7:η′  
_tdb: _tdb:AlCu-21Kro.tdb:ALCU_ETA_LT  


### TDB models of ALCU_ETA_LT (1): PHASE and CONSTITUENT statements as written

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): ALCU_ETA_LT, type code %, sha256 `bd06016e51db2bef…`

~~~~text
50: PHASE ALCU_ETA_LT % 2 1 1 !
51: CONST ALCU_ETA_LT : AL% CU : CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## ALCU3_D022 (Al–Cu)

- Id: `phase:al-cu:alcu3-d022`; status `needs_review`
- No structure assigned. Why: assessment_declared_blocked_by:stoichiometry_contradicts_D0_22; stoichiometry_contradicts_D0_22:AlCu-15Lia.tdb; stoichiometry_contradicts_D0_22:AlCu-21Kro.tdb
- Candidate (name_token): Al3Ti · D0_22 · tI8 · I4/mmm (139) — Strukturbericht/word 'D022' in the TDB name
- Candidate (sgte_mmc2): Al3Ti · D0_22 · tI8 · I4/mmm (139) — Hallstedt 2025 mmc2 row for ALCU3_D022: AlCu3
- Candidate (tdb_comment): Al3Ti · tI8 · I4/mmm — AlCu-15Lia.tdb: 'Prototype Al3Ti (tI8, I4/mmm) alpha-2'
- Candidate (tdb_comment): Al3Ti · tI8 · I4/mmm — AlCu-21Kro.tdb: 'Prototype Al3Ti (tI8, I4/mmm), alpha-2/prime'
- Stoichiometry: Al 0.2300, Cu 0.7700
- Stability: stable in 2 of 2 calculated diagram(s): 300–640 K, x(Cu) 0.77–0.77
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:alcu3-d022)

Names (3): _corpus: _corpus:phase:al-cu:alcu3-d022  
_tdb: _tdb:AlCu-15Lia.tdb:ALCU3_D022, tdb:AlCu-21Kro.tdb:ALCU3_D022  


### TDB models of ALCU3_D022 (2): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): ALCU3_D022, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
92: PHASE ALCU3_D022 % 2 0.23 0.77 !
93: CONST ALCU3_D022 : AL : CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): ALCU3_D022, type code %, sha256 `bd06016e51db2bef…`

~~~~text
92: PHASE ALCU3_D022 % 2 0.23 0.77 !
93: CONST ALCU3_D022 : AL : CU : !
~~~~

Example references (2 of 2; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase_

## BCC_A2 (Al–Cu)

- Id: `phase:al-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: stable in 5 of 5 calculated diagram(s): 300–1329.45 K, x(Cu) 0.32085–0.81606
- Literature: 38 values (35 accepted) from 3 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:bcc-a2)

Names (11): _corpus: _corpus:phase:al-cu:bcc-a2  
_paper: _paper:10.1007/s10853-020-05423-7:β, paper:10.1007/s11661-002-0173-7:Bcc, paper:10.1007/s11661-002-0173-7:bcc, paper:sha256-85fd53a1a176b694:bcc-A2  
_system_alias: _system_alias:al-cu:beta  
_tdb: _tdb:AlCu-02Mie.tdb:BCC_A2, tdb:AlCu-04Wit.tdb:BCC_A2, tdb:AlCu-15Lia.tdb:BCC_A2, tdb:AlCu-21Kro.tdb:BCC_A2, tdb:AlCu-98Sau-LB.tdb:BCC_A2  


### TDB models of BCC_A2 (5): PHASE and CONSTITUENT statements as written

[AlCu-02Mie.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-02Mie.tdb): BCC_A2, type code %B, sha256 `3831fc8d892fc077…`

~~~~text
33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : AL CU : VA : !
~~~~

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): BCC_A2, type code %B, sha256 `7239fc4da5e79f40…`

~~~~text
50: PHASE BCC_A2 %B 2 1 3 !
51: CONST BCC_A2 : AL CU : VA : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): BCC_A2, type code %B, sha256 `cc9baa9f2479820c…`

~~~~text
40: PHASE BCC_A2 %B 2 1 3 !
41: CONST BCC_A2 : AL CU : VA : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): BCC_A2, type code %B, sha256 `bd06016e51db2bef…`

~~~~text
35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : AL CU : VA : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): BCC_A2, type code %B, sha256 `bed1eea6f6cf10b8…`

~~~~text
47: PHASE BCC_A2 %B 2 1 3 !
48: CONST BCC_A2 : AL CU : VA : !
~~~~

Example references (6 of 6; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1007/s11661-002-0173-7](https://doi.org/10.1007/s11661-002-0173-7) J. Miettinen, Thermodynamic description of the Cu-Al-Sn system in the copper-rich corner, Metall Mater Trans A 33, 1639-1648 (2002).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_
- [doi:10.1179/imr.1985.30.1.211](https://doi.org/10.1179/imr.1985.30.1.211) J. L. Murray, The aluminium-copper system, International Materials Reviews 30, 211-234 (1985).  
_cited as the source of values for this phase_

## GAMMA_D82 (Al–Cu)

- Id: `phase:al-cu:d82-gamma`; status `assigned`
- Structure: Cu5Zn8 · D8_2 · cI52 · I-43m (217); type `st:d8-2-cu5zn8-ci52`; tier A: standard phase name; confidence high
- Caveat: partitioned order/disorder model in AlCu-21Kro.tdb also describes the disordered state
- Stability: stable in 2 of 2 calculated diagram(s): 1050.72–1286.31 K, x(Cu) 0.64361–0.69815
- Literature: 16 values (16 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:d82-gamma)

Names (5): _corpus: _corpus:phase:al-cu:d82-gamma, corpus:phase:al-cu:gamma-d82  
_paper: _paper:10.1007/s10853-020-05423-7:γ  
_tdb: _tdb:AlCu-15Lia.tdb:GAMMA_D82, tdb:AlCu-21Kro.tdb:GAMMA_D82  


### TDB models of GAMMA_D82 (2): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): GAMMA_D82, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
82: PHASE GAMMA_D82 % 3 4 6 16 !
83: CONST GAMMA_D82 : CU : CU : AL CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): GAMMA_D82, type code %, sha256 `bd06016e51db2bef…`

~~~~text
87: PHASE GAMMA_D82 % 4 2 2 3 6 !
88: CONST GAMMA_D82 : AL CU : CU : CU : AL CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## GAMMA_D83 (Al–Cu)

- Id: `phase:al-cu:d83-gamma`; status `assigned`
- Structure: Al4Cu9 · D8_3 · cP52 · P-43m (215); type `st:d8-3-al4cu9-cp52`; tier A: standard phase name; confidence high
- Caveat: partitioned order/disorder model in AlCu-21Kro.tdb also describes the disordered state
- Stability: stable in 2 of 2 calculated diagram(s): 300–1145.67 K, x(Cu) 0.62085–0.69906
- Literature: 20 values (20 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:d83-gamma)

Names (5): _corpus: _corpus:phase:al-cu:d83-gamma, corpus:phase:al-cu:gamma-d83  
_paper: _paper:10.1007/s10853-020-05423-7:γ′  
_tdb: _tdb:AlCu-15Lia.tdb:GAMMA_D83, tdb:AlCu-21Kro.tdb:GAMMA_D83  


### TDB models of GAMMA_D83 (2): PHASE and CONSTITUENT statements as written

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): GAMMA_D83, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
87: PHASE GAMMA_D83 % 3 4 6 16 !
88: CONST GAMMA_D83 : CU : CU : AL CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): GAMMA_D83, type code %, sha256 `bd06016e51db2bef…`

~~~~text
82: PHASE GAMMA_D83 % 4 2 2 3 6 !
83: CONST GAMMA_D83 : AL CU : CU : CU : AL CU : !
~~~~

Example references (3 of 3; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_

## FCC_A1 (Al–Cu)

- Id: `phase:al-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 5 of 5 calculated diagram(s): 300–1358.62 K, x(Cu) 0–1
- Literature: 16 values (16 accepted) from 3 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:fcc-a1)

Names (9): _corpus: _corpus:phase:al-cu:fcc-a1  
_paper: _paper:10.1007/s10853-020-05423-7:(Cu), paper:10.1007/s11661-002-0173-7:Fcc, paper:sha256-85fd53a1a176b694:fcc-A1  
_tdb: _tdb:AlCu-02Mie.tdb:FCC_A1, tdb:AlCu-04Wit.tdb:FCC_A1, tdb:AlCu-15Lia.tdb:FCC_A1, tdb:AlCu-21Kro.tdb:FCC_A1, tdb:AlCu-98Sau-LB.tdb:FCC_A1  


### TDB models of FCC_A1 (5): PHASE and CONSTITUENT statements as written

[AlCu-02Mie.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-02Mie.tdb): FCC_A1, type code %A, sha256 `3831fc8d892fc077…`

~~~~text
28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : AL CU : VA : !
~~~~

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): FCC_A1, type code %A, sha256 `7239fc4da5e79f40…`

~~~~text
45: PHASE FCC_A1 %A 2 1 1 !
46: CONST FCC_A1 : AL% CU% : VA : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): FCC_A1, type code %A, sha256 `cc9baa9f2479820c…`

~~~~text
35: PHASE FCC_A1 %A 2 1 1 !
36: CONST FCC_A1 : AL% CU% : VA : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): FCC_A1, type code %A, sha256 `bd06016e51db2bef…`

~~~~text
30: PHASE FCC_A1 %A 2 1 1 !
31: CONST FCC_A1 : AL% CU% : VA : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): FCC_A1, type code %A, sha256 `bed1eea6f6cf10b8…`

~~~~text
42: PHASE FCC_A1 %A 2 1 1 !
43: CONST FCC_A1 : AL% CU% : VA : !
~~~~

Example references (6 of 6; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1007/s11661-002-0173-7](https://doi.org/10.1007/s11661-002-0173-7) J. Miettinen, Thermodynamic description of the Cu-Al-Sn system in the copper-rich corner, Metall Mater Trans A 33, 1639-1648 (2002).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_
- [doi:10.1179/imr.1985.30.1.211](https://doi.org/10.1179/imr.1985.30.1.211) J. L. Murray, The aluminium-copper system, International Materials Reviews 30, 211-234 (1985).  
_cited as the source of values for this phase_

## HCP_A3 (Al–Cu)

- Id: `phase:al-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: stable in 1 of 5 calculated diagram(s): 747.05–1015.23 K, x(Cu) 0.26592–0.37287
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:hcp-a3)

Names (6): _corpus: _corpus:phase:al-cu:hcp-a3  
_tdb: _tdb:AlCu-02Mie.tdb:HCP_A3, tdb:AlCu-04Wit.tdb:HCP_A3, tdb:AlCu-15Lia.tdb:HCP_A3, tdb:AlCu-21Kro.tdb:HCP_A3, tdb:AlCu-98Sau-LB.tdb:HCP_A3  


### TDB models of HCP_A3 (5): PHASE and CONSTITUENT statements as written

[AlCu-02Mie.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-02Mie.tdb): HCP_A3, type code %A, sha256 `3831fc8d892fc077…`

~~~~text
38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : AL CU : VA : !
~~~~

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): HCP_A3, type code %A, sha256 `7239fc4da5e79f40…`

~~~~text
55: PHASE HCP_A3 %A 2 1 0.5 !
56: CONST HCP_A3 : AL CU : VA : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): HCP_A3, type code %A, sha256 `cc9baa9f2479820c…`

~~~~text
45: PHASE HCP_A3 %A 2 1 0.5 !
46: CONST HCP_A3 : AL CU : VA : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): HCP_A3, type code %A, sha256 `bd06016e51db2bef…`

~~~~text
40: PHASE HCP_A3 %A 2 1 0.5 !
41: CONST HCP_A3 : AL CU : VA : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): HCP_A3, type code %A, sha256 `bed1eea6f6cf10b8…`

~~~~text
52: PHASE HCP_A3 %A 2 1 0.5 !
53: CONST HCP_A3 : AL CU : VA : !
~~~~

Example references (4 of 4; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase_
- [doi:10.1007/s11661-002-0173-7](https://doi.org/10.1007/s11661-002-0173-7) J. Miettinen, Thermodynamic description of the Cu-Al-Sn system in the copper-rich corner, Metall Mater Trans A 33, 1639-1648 (2002).  
_assessment that models this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_

## LIQUID (Al–Cu)

- Id: `phase:al-cu:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 5 of 5 calculated diagram(s): 820.61–2500 K, x(Cu) 0–1
- Literature: 42 values (39 accepted) from 3 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:al-cu:liquid)

Names (10): _corpus: _corpus:phase:al-cu:liquid  
_paper: _paper:10.1007/s10853-020-05423-7:liq, paper:10.1007/s10853-020-05423-7:liq., paper:10.1007/s11661-002-0173-7:L, paper:sha256-85fd53a1a176b694:Liquid  
_tdb: _tdb:AlCu-02Mie.tdb:LIQUID, tdb:AlCu-04Wit.tdb:LIQUID, tdb:AlCu-15Lia.tdb:LIQUID, tdb:AlCu-21Kro.tdb:LIQUID, tdb:AlCu-98Sau-LB.tdb:LIQUID  


### TDB models of LIQUID (5): PHASE and CONSTITUENT statements as written

[AlCu-02Mie.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-02Mie.tdb): LIQUID, type code %, sha256 `3831fc8d892fc077…`

~~~~text
23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : AL CU : !
~~~~

[AlCu-04Wit.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-04Wit.tdb): LIQUID, type code %, sha256 `7239fc4da5e79f40…`

~~~~text
40: PHASE LIQUID:L % 1 1 !
41: CONST LIQUID:L : AL CU : !
~~~~

[AlCu-15Lia.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-15Lia.tdb): LIQUID, type code %, sha256 `cc9baa9f2479820c…`

~~~~text
30: PHASE LIQUID:L % 1 1 !
31: CONST LIQUID:L : AL CU : !
~~~~

[AlCu-21Kro.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-21Kro.tdb): LIQUID, type code %, sha256 `bd06016e51db2bef…`

~~~~text
25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : AL CU : !
~~~~

[AlCu-98Sau-LB.tdb](https://orchid-project.org/data/databases/sgte-binary/AlCu-98Sau-LB.tdb): LIQUID, type code %, sha256 `bed1eea6f6cf10b8…`

~~~~text
37: PHASE LIQUID:L % 1 1 !
38: CONST LIQUID:L : AL CU : !
~~~~

Example references (6 of 6; assessments first): 

- [doi:10.1007/s10853-020-05423-7](https://doi.org/10.1007/s10853-020-05423-7) Aleš Kroupa, Ondřej Zobač, Klaus W. Richter, The thermodynamic reassessment of the binary Al–Cu system, J Mater Sci 56, 3430-3443 (2021).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.calphad.2015.10.004](https://doi.org/10.1016/j.calphad.2015.10.004) Liang SM, Schmid-Fetzer R (2015) Thermodynamic assessment of the Al–Cu–Zn system, part II: Al–Cu binary system. CALPHAD 51:252–260  
_assessment that models this phase; cited as the source of values for this phase_
- [doi:10.1007/s11661-002-0173-7](https://doi.org/10.1007/s11661-002-0173-7) J. Miettinen, Thermodynamic description of the Cu-Al-Sn system in the copper-rich corner, Metall Mater Trans A 33, 1639-1648 (2002).  
_assessment that models this phase; reports values for this phase_
- [doi:10.1016/j.jallcom.2004.04.126](https://doi.org/10.1016/j.jallcom.2004.04.126) V.T. Witusiewicz, U. Hecht, S.G. Fries, S. Rex, The Ag–Al–Cu system, Journal of Alloys and Compounds 385, 133-143 (2004).  
_assessment that models this phase_
- [doi:10.1016/j.intermet.2011.07.007](https://doi.org/10.1016/j.intermet.2011.07.007) Norbert Ponweiser, Christian L. Lengauer, Klaus W. Richter, Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu, Intermetallics 19, 1737-1746 (2011).  
_cited as the source of values for this phase_
- [doi:10.1179/imr.1985.30.1.211](https://doi.org/10.1179/imr.1985.30.1.211) J. L. Murray, The aluminium-copper system, International Materials Reviews 30, 211-234 (1985).  
_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).