Am–U phases

7 phases (tier A 5, liquid 1, needs_review 1); 6 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 · full JSON · Am–U system page · Markdown · field reference

Phases of the Am–U system (7)
Phase	Structure	Basis	Stability (calculated)	TDB models
ORTHORHOMBIC_A20 phase:am-u:a20-orthorhombic	alpha-U · A20 · oC4 · Cmcm (63)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 300–942.02 K, x(U) 0.9991–1	3
BCC_A2 phase:am-u:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 1009.45–2104.33 K, x(U) 0–1	3
DHCP phase:am-u:dhcp-a3	alpha-La · A3' · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 300–1364.47 K, x(U) 0–0.00178	3
FCC_A1 phase:am-u:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 902.68–1400 K, x(U) 0–0.41	3
HCP_A3 phase:am-u:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 3 calculated diagram(s)	3
LIQUID phase:am-u:liquid	liquid	liquid	stable in 3 of 3 calculated diagram(s): 1354.65–4000 K, x(U) 0–1	3
TETRAGONAL_U phase:am-u:u-tetragonal		needs_review	stable in 3 of 3 calculated diagram(s): 942.02–1406.31 K, x(U) 0.99816–1	3

ORTHORHOMBIC_A20 (Am–U)

Id: phase:am-u:a20-orthorhombic; status assigned
Structure: alpha-U · A20 · oC4 · Cmcm (63); type st:a20-alpha-u-oc4; tier A: standard phase name; confidence high
Stability: stable in 3 of 3 calculated diagram(s): 300–942.02 K, x(U) 0.9991–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:a20-orthorhombic
tdb: tdb:AmU-10Kur.tdb:ORTHORHOMBIC_A20, tdb:AmU-15Per.tdb:ORTHORHOMBIC_A20, tdb:AmU-93Oga.tdb:ORTHORHOMBIC_A20

TDB models of ORTHORHOMBIC_A20 (3): PHASE and CONSTITUENT statements as written

AmU-10Kur.tdb: ORTHORHOMBIC_A20, type code %, sha256 d0aa112b9c5e85f9…

45: PHASE ORTHORHOMBIC_A20 % 1 1 !
46: CONST ORTHORHOMBIC_A20 : AM U% : !

AmU-15Per.tdb: ORTHORHOMBIC_A20, type code %, sha256 b45bb49962d3127b…

46: PHASE ORTHORHOMBIC_A20 % 1 1 !
47: CONST ORTHORHOMBIC_A20 : U : !

AmU-93Oga.tdb: ORTHORHOMBIC_A20, type code %, sha256 a402906c7e81f20b…

49: PHASE ORTHORHOMBIC_A20 % 1 1 !
50: CONST ORTHORHOMBIC_A20 : U : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

BCC_A2 (Am–U)

Id: phase:am-u: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 3 of 3 calculated diagram(s): 1009.45–2104.33 K, x(U) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:bcc-a2
tdb: tdb:AmU-10Kur.tdb:BCC_A2, tdb:AmU-15Per.tdb:BCC_A2, tdb:AmU-93Oga.tdb:BCC_A2

TDB models of BCC_A2 (3): PHASE and CONSTITUENT statements as written

AmU-10Kur.tdb: BCC_A2, type code %B, sha256 d0aa112b9c5e85f9…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : AM% U% : VA : !

AmU-15Per.tdb: BCC_A2, type code %B, sha256 b45bb49962d3127b…

31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : AM% U% : VA : !

AmU-93Oga.tdb: BCC_A2, type code %B, sha256 a402906c7e81f20b…

34: PHASE BCC_A2 %B 2 1 3 !
35: CONST BCC_A2 : AM% U% : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

DHCP (Am–U)

Id: phase:am-u:dhcp-a3; status assigned
Structure: alpha-La · A3' · hP4 · P6_3/mmc (194); type st:a3-alpha-la-hp4; tier A: standard phase name; confidence high
Stability: stable in 3 of 3 calculated diagram(s): 300–1364.47 K, x(U) 0–0.00178
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:dhcp-a3
tdb: tdb:AmU-10Kur.tdb:DHCP, tdb:AmU-15Per.tdb:DHCP, tdb:AmU-93Oga.tdb:DHCP

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

AmU-10Kur.tdb: DHCP, type code %, sha256 d0aa112b9c5e85f9…

40: PHASE DHCP % 1 1 !
41: CONST DHCP : AM% U : !

AmU-15Per.tdb: DHCP, type code %, sha256 b45bb49962d3127b…

41: PHASE DHCP % 1 1 !
42: CONST DHCP : AM : !

AmU-93Oga.tdb: DHCP, type code %, sha256 a402906c7e81f20b…

44: PHASE DHCP % 1 1 !
45: CONST DHCP : AM : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

FCC_A1 (Am–U)

Id: phase:am-u: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 3 of 3 calculated diagram(s): 902.68–1400 K, x(U) 0–0.41
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:fcc-a1
tdb: tdb:AmU-10Kur.tdb:FCC_A1, tdb:AmU-15Per.tdb:FCC_A1, tdb:AmU-93Oga.tdb:FCC_A1

TDB models of FCC_A1 (3): PHASE and CONSTITUENT statements as written

AmU-10Kur.tdb: FCC_A1, type code %A, sha256 d0aa112b9c5e85f9…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : AM% U : VA : !

AmU-15Per.tdb: FCC_A1, type code %A, sha256 b45bb49962d3127b…

26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : AM% U : VA : !

AmU-93Oga.tdb: FCC_A1, type code %A, sha256 a402906c7e81f20b…

29: PHASE FCC_A1 %A 2 1 1 !
30: CONST FCC_A1 : AM% U : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

HCP_A3 (Am–U)

Id: phase:am-u: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 3 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:hcp-a3
tdb: tdb:AmU-10Kur.tdb:HCP_A3, tdb:AmU-15Per.tdb:HCP_A3, tdb:AmU-93Oga.tdb:HCP_A3

TDB models of HCP_A3 (3): PHASE and CONSTITUENT statements as written

AmU-10Kur.tdb: HCP_A3, type code %A, sha256 d0aa112b9c5e85f9…

35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : AM U : VA : !

AmU-15Per.tdb: HCP_A3, type code %A, sha256 b45bb49962d3127b…

36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : AM U : VA : !

AmU-93Oga.tdb: HCP_A3, type code %A, sha256 a402906c7e81f20b…

39: PHASE HCP_A3 %A 2 1 0.5 !
40: CONST HCP_A3 : AM U : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

LIQUID (Am–U)

Id: phase:am-u:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 3 of 3 calculated diagram(s): 1354.65–4000 K, x(U) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:liquid
tdb: tdb:AmU-10Kur.tdb:LIQUID, tdb:AmU-15Per.tdb:LIQUID, tdb:AmU-93Oga.tdb:LIQUID

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

AmU-10Kur.tdb: LIQUID, type code %, sha256 d0aa112b9c5e85f9…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : AM U : !

AmU-15Per.tdb: LIQUID, type code %, sha256 b45bb49962d3127b…

21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : AM U : !

AmU-93Oga.tdb: LIQUID, type code %, sha256 a402906c7e81f20b…

24: PHASE LIQUID:L % 1 1 !
25: CONST LIQUID:L : AM U : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase

TETRAGONAL_U (Am–U)

Id: phase:am-u:u-tetragonal; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:TETRAGONAL; no_structure_token
Candidate (sgte_mmc2): beta-U · A_b · tP30 · P4_2/mnm (136) — Hallstedt 2025 mmc2 row for TETRAGONAL_U: beta-U
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — AmU-10Kur.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — AmU-15Per.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — AmU-93Oga.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Stability: stable in 3 of 3 calculated diagram(s): 942.02–1406.31 K, x(U) 0.99816–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:am-u:u-tetragonal
tdb: tdb:AmU-10Kur.tdb:TETRAGONAL_U, tdb:AmU-15Per.tdb:TETRAGONAL_U, tdb:AmU-93Oga.tdb:TETRAGONAL_U

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

AmU-10Kur.tdb: TETRAGONAL_U, type code %, sha256 d0aa112b9c5e85f9…

50: PHASE TETRAGONAL_U % 1 1 !
51: CONST TETRAGONAL_U : AM U% : !

AmU-15Per.tdb: TETRAGONAL_U, type code %, sha256 b45bb49962d3127b…

51: PHASE TETRAGONAL_U % 1 1 !
52: CONST TETRAGONAL_U : U : !

AmU-93Oga.tdb: TETRAGONAL_U, type code %, sha256 a402906c7e81f20b…

54: PHASE TETRAGONAL_U % 1 1 !
55: CONST TETRAGONAL_U : U : !

Example references (2 of 2; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
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). doi: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). doi: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.

@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}
}