U–W phases

6 phases (tier A 4, liquid 1, needs_review 1); 4 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 · U–W system page · Markdown · field reference

Phases of the U–W system (6)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
ORTHORHOMBIC_A20 phase:u-w:a20-orthorhombic	alpha-U · A20 · oC4 · Cmcm (63)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–947.02 K, x(W) 0–0	0	2
BCC_A2 phase:u-w:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–3999.88 K, x(W) 0–1	7	2
FCC_A1 phase:u-w:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	2
HCP_A3 phase:u-w: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:u-w:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 1404.22–4000 K, x(W) 0–1	19	2
TETRAGONAL_U phase:u-w:u-tetragonal		needs_review	stable in 2 of 2 calculated diagram(s): 942.02–1089.95 K, x(W) 0–1e-05	2	2

ORTHORHOMBIC_A20 (U–W)

Id: phase:u-w:a20-orthorhombic; status assigned
Structure: alpha-U · A20 · oC4 · Cmcm (63); type st:a20-alpha-u-oc4; tier A: standard phase name; confidence high
Stoichiometry: U 1.0000
Stability: stable in 2 of 2 calculated diagram(s): 300–947.02 K, x(W) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:u-w:a20-orthorhombic, corpus:phase:u-w:orthorhombic-a20
tdb: tdb:UW-08Wan.tdb:ORTHORHOMBIC_A20, tdb:UW-11Ber.tdb:ORTHORHOMBIC_A20

TDB models of ORTHORHOMBIC_A20 (2): PHASE and CONSTITUENT statements as written

UW-08Wan.tdb: ORTHORHOMBIC_A20, type code %, sha256 b39bc5b283c025c0…

40: PHASE ORTHORHOMBIC_A20 % 1 1 !
41: CONST ORTHORHOMBIC_A20 : U : !

UW-11Ber.tdb: ORTHORHOMBIC_A20, type code %, sha256 4aad821713451c83…

41: PHASE ORTHORHOMBIC_A20 % 1 1 !
42: CONST ORTHORHOMBIC_A20 : U : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
assessment that models this phase
doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase

BCC_A2 (U–W)

Id: phase:u-w: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 2 of 2 calculated diagram(s): 300–3999.88 K, x(W) 0–1
Literature: 7 values (7 accepted) from 2 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:u-w:bcc-a2
paper: paper:10.1016/j.jnucmat.2008.07.009:bcc (W), paper:10.1016/j.jnucmat.2011.01.043:(W), paper:10.1016/j.jnucmat.2011.01.043:(γ-U)
tdb: tdb:UW-08Wan.tdb:BCC_A2, tdb:UW-11Ber.tdb:BCC_A2

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

UW-08Wan.tdb: BCC_A2, type code %B, sha256 b39bc5b283c025c0…

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

UW-11Ber.tdb: BCC_A2, type code %B, sha256 4aad821713451c83…

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

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase; reports values for this phase

FCC_A1 (U–W)

Id: phase:u-w:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; 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

Names (3): corpus: corpus:phase:u-w:fcc-a1
tdb: tdb:UW-08Wan.tdb:FCC_A1, tdb:UW-11Ber.tdb:FCC_A1

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

UW-08Wan.tdb: FCC_A1, type code %A, sha256 b39bc5b283c025c0…

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

UW-11Ber.tdb: FCC_A1, type code %A, sha256 4aad821713451c83…

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

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
assessment that models this phase
doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase

HCP_A3 (U–W)

Id: phase:u-w: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

Names (3): corpus: corpus:phase:u-w:hcp-a3
tdb: tdb:UW-08Wan.tdb:HCP_A3, tdb:UW-11Ber.tdb:HCP_A3

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

UW-08Wan.tdb: HCP_A3, type code %A, sha256 b39bc5b283c025c0…

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

UW-11Ber.tdb: HCP_A3, type code %A, sha256 4aad821713451c83…

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

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
assessment that models this phase
doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase

LIQUID (U–W)

Id: phase:u-w:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 1404.22–4000 K, x(W) 0–1
Literature: 19 values (19 accepted) from 2 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:u-w:liquid
paper: paper:10.1016/j.jnucmat.2008.07.009:L, paper:10.1016/j.jnucmat.2008.07.009:liquid, paper:10.1016/j.jnucmat.2011.01.043:L
tdb: tdb:UW-08Wan.tdb:LIQUID, tdb:UW-11Ber.tdb:LIQUID

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

UW-08Wan.tdb: LIQUID, type code %, sha256 b39bc5b283c025c0…

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

UW-11Ber.tdb: LIQUID, type code %, sha256 4aad821713451c83…

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

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase; reports values for this phase

TETRAGONAL_U (U–W)

Id: phase:u-w: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 — UW-08Wan.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — UW-11Ber.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Stability: stable in 2 of 2 calculated diagram(s): 942.02–1089.95 K, x(W) 0–1e-05
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:u-w:u-tetragonal, corpus:phase:u-w:tetragonal-u
paper: paper:10.1016/j.jnucmat.2011.01.043:(β-U)
tdb: tdb:UW-08Wan.tdb:TETRAGONAL_U, tdb:UW-11Ber.tdb:TETRAGONAL_U

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

UW-08Wan.tdb: TETRAGONAL_U, type code %, sha256 b39bc5b283c025c0…

45: PHASE TETRAGONAL_U % 1 1 !
46: CONST TETRAGONAL_U : U : !

UW-11Ber.tdb: TETRAGONAL_U, type code %, sha256 4aad821713451c83…

46: PHASE TETRAGONAL_U % 1 1 !
47: CONST TETRAGONAL_U : U% W : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2011.01.043 A. Berche, N. Dupin, C. Guéneau, C. Rado, B. Sundman, J.C. Dumas, Calphad thermodynamic description of some binary systems involving U, Journal of Nuclear Materials 411, 131-143 (2011).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnucmat.2008.07.009 J. Wang, X.J. Liu, C.P. Wang, Thermodynamic calculation of phase equilibria of the U–Ga and U–W systems, Journal of Nuclear Materials 380, 105-110 (2008).
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}
}