Ta–W phases

5 phases (tier A 4, liquid 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 · full JSON · Ta–W system page · Markdown · field reference

Phases of the Ta–W system (5)
Phase	Structure	Basis	Stability (calculated)	TDB models
BCC_A2 phase:ta-w:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–3999.9 K, x(W) 0–1	6
B2_BCC phase:ta-w:bcc-b2	CsCl · B2 · cP2 · Pm-3m (221)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–3690 K, x(W) 0.16–0.97	2
FCC_A1 phase:ta-w:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 4 calculated diagram(s)	4
HCP_A3 phase:ta-w:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 4 calculated diagram(s)	4
LIQUID phase:ta-w:liquid	liquid	liquid	stable in 4 of 4 calculated diagram(s): 3287–4000 K, x(W) 0–1	4

BCC_A2 (Ta–W)

Id: phase:ta-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 4 of 4 calculated diagram(s): 300–3999.9 K, x(W) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:ta-w:bcc-a2
tdb: tdb:TaW-01Kau-LB.tdb:A2_BCC, tdb:TaW-01Kau-LB.tdb:BCC_A2, tdb:TaW-14Guo.tdb:BCC_A2, tdb:TaW-22Zha.tdb:A2_BCC, tdb:TaW-22Zha.tdb:BCC_A2, tdb:TaW-95Fer.tdb:BCC_A2

TDB models of BCC_A2 (6): PHASE and CONSTITUENT statements as written

TaW-01Kau-LB.tdb: A2_BCC, type code %B, sha256 06799384d8b11b4b…

45: PHASE A2_BCC %B 2 1 3 !
46: CONST A2_BCC : TA W : VA : !

TaW-01Kau-LB.tdb: BCC_A2, type code %B, sha256 06799384d8b11b4b…

40: PHASE BCC_A2 %B 2 1 3 !
41: CONST BCC_A2 : TA% W% : VA : !

TaW-14Guo.tdb: BCC_A2, type code %B, sha256 e48b844bab28b6a1…

29: PHASE BCC_A2 %B 2 1 3 !
30: CONST BCC_A2 : TA% W% : VA : !

TaW-22Zha.tdb: A2_BCC, type code %B, sha256 3daec7c0661909a7…

42: PHASE A2_BCC %B 2 1 3 !
43: CONST A2_BCC : TA W : VA : !

TaW-22Zha.tdb: BCC_A2, type code %B, sha256 3daec7c0661909a7…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : TA% W% : VA : !

TaW-95Fer.tdb: BCC_A2, type code %B, sha256 50f38ebf2b2eefbf…

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

Example references (3 of 3; assessments first):

doi:10.1016/j.ijrmhm.2022.105780 Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang, On phase stability of Mo-Nb-Ta-W refractory high entropy alloys, International Journal of Refractory Metals and Hard Materials 103, 105780 (2022).
assessment that models this phase
doi:10.1016/S0364-5916(01)00061-X L. Kaufman, P.E.A. Turchi, W. Huang, Z.-K. Liu, Calphad, 25, 419-33(2001).
assessment that models this phase
doi:10.3139/146.111125 C. Guo, C. Li, S. Shang, Z. Du, Thermodynamic description of the Ta–W–Zr system, Int. J. Mater. Res. 105 (11) (2014) 1048–1056.
assessment that models this phase

B2_BCC (Ta–W)

Id: phase:ta-w:bcc-b2; status assigned
Structure: CsCl · B2 · cP2 · Pm-3m (221); type st:b2-cscl-cp2; tier A: standard phase name; confidence high
Caveat: TaW-01Kau-LB.tdb: ordered phase with disordered part A2_BCC (order/disorder model)
Caveat: TaW-22Zha.tdb: ordered phase with disordered part A2_BCC (order/disorder model)
Caveat: partitioned order/disorder model in TaW-01Kau-LB.tdb also describes the disordered state
Caveat: partitioned order/disorder model in TaW-22Zha.tdb also describes the disordered state
Stability: stable in 2 of 2 calculated diagram(s): 300–3690 K, x(W) 0.16–0.97
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:ta-w:bcc-b2
tdb: tdb:TaW-01Kau-LB.tdb:B2_BCC, tdb:TaW-22Zha.tdb:B2_BCC

TDB models of B2_BCC (2): PHASE and CONSTITUENT statements as written

TaW-01Kau-LB.tdb: B2_BCC, type code %BO, sha256 06799384d8b11b4b…

50: PHASE B2_BCC %BO 3 0.5 0.5 3 !
51: CONST B2_BCC : TA W : TA W : VA : !

TaW-22Zha.tdb: B2_BCC, type code %BO, sha256 3daec7c0661909a7…

47: PHASE B2_BCC %BO 3 0.5 0.5 3 !
48: CONST B2_BCC : TA W : TA W : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.ijrmhm.2022.105780 Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang, On phase stability of Mo-Nb-Ta-W refractory high entropy alloys, International Journal of Refractory Metals and Hard Materials 103, 105780 (2022).
assessment that models this phase
doi:10.1016/S0364-5916(01)00061-X L. Kaufman, P.E.A. Turchi, W. Huang, Z.-K. Liu, Calphad, 25, 419-33(2001).
assessment that models this phase

FCC_A1 (Ta–W)

Id: phase:ta-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 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:ta-w:fcc-a1
tdb: tdb:TaW-01Kau-LB.tdb:FCC_A1, tdb:TaW-14Guo.tdb:FCC_A1, tdb:TaW-22Zha.tdb:FCC_A1, tdb:TaW-95Fer.tdb:FCC_A1

TDB models of FCC_A1 (4): PHASE and CONSTITUENT statements as written

TaW-01Kau-LB.tdb: FCC_A1, type code %A, sha256 06799384d8b11b4b…

35: PHASE FCC_A1 %A 2 1 1 !
36: CONST FCC_A1 : TA W : VA : !

TaW-14Guo.tdb: FCC_A1, type code %A, sha256 e48b844bab28b6a1…

24: PHASE FCC_A1 %A 2 1 1 !
25: CONST FCC_A1 : TA W : VA : !

TaW-22Zha.tdb: FCC_A1, type code %A, sha256 3daec7c0661909a7…

32: PHASE FCC_A1 %A 2 1 1 !
33: CONST FCC_A1 : TA W : VA : !

TaW-95Fer.tdb: FCC_A1, type code %A, sha256 50f38ebf2b2eefbf…

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

Example references (3 of 3; assessments first):

doi:10.1016/j.ijrmhm.2022.105780 Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang, On phase stability of Mo-Nb-Ta-W refractory high entropy alloys, International Journal of Refractory Metals and Hard Materials 103, 105780 (2022).
assessment that models this phase
doi:10.1016/S0364-5916(01)00061-X L. Kaufman, P.E.A. Turchi, W. Huang, Z.-K. Liu, Calphad, 25, 419-33(2001).
assessment that models this phase
doi:10.3139/146.111125 C. Guo, C. Li, S. Shang, Z. Du, Thermodynamic description of the Ta–W–Zr system, Int. J. Mater. Res. 105 (11) (2014) 1048–1056.
assessment that models this phase

HCP_A3 (Ta–W)

Id: phase:ta-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 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:ta-w:hcp-a3
tdb: tdb:TaW-01Kau-LB.tdb:HCP_A3, tdb:TaW-14Guo.tdb:HCP_A3, tdb:TaW-22Zha.tdb:HCP_A3, tdb:TaW-95Fer.tdb:HCP_A3

TDB models of HCP_A3 (4): PHASE and CONSTITUENT statements as written

TaW-01Kau-LB.tdb: HCP_A3, type code %A, sha256 06799384d8b11b4b…

55: PHASE HCP_A3 %A 2 1 0.5 !
56: CONST HCP_A3 : TA W : VA : !

TaW-14Guo.tdb: HCP_A3, type code %A, sha256 e48b844bab28b6a1…

34: PHASE HCP_A3 %A 2 1 0.5 !
35: CONST HCP_A3 : TA W : VA : !

TaW-22Zha.tdb: HCP_A3, type code %A, sha256 3daec7c0661909a7…

52: PHASE HCP_A3 %A 2 1 0.5 !
53: CONST HCP_A3 : TA W : VA : !

TaW-95Fer.tdb: HCP_A3, type code %A, sha256 50f38ebf2b2eefbf…

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

Example references (3 of 3; assessments first):

doi:10.1016/j.ijrmhm.2022.105780 Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang, On phase stability of Mo-Nb-Ta-W refractory high entropy alloys, International Journal of Refractory Metals and Hard Materials 103, 105780 (2022).
assessment that models this phase
doi:10.1016/S0364-5916(01)00061-X L. Kaufman, P.E.A. Turchi, W. Huang, Z.-K. Liu, Calphad, 25, 419-33(2001).
assessment that models this phase
doi:10.3139/146.111125 C. Guo, C. Li, S. Shang, Z. Du, Thermodynamic description of the Ta–W–Zr system, Int. J. Mater. Res. 105 (11) (2014) 1048–1056.
assessment that models this phase

LIQUID (Ta–W)

Id: phase:ta-w:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 3287–4000 K, x(W) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:ta-w:liquid
tdb: tdb:TaW-01Kau-LB.tdb:LIQUID, tdb:TaW-14Guo.tdb:LIQUID, tdb:TaW-22Zha.tdb:LIQUID, tdb:TaW-95Fer.tdb:LIQUID

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

TaW-01Kau-LB.tdb: LIQUID, type code %, sha256 06799384d8b11b4b…

30: PHASE LIQUID:L % 1 1 !
31: CONST LIQUID:L : TA W : !

TaW-14Guo.tdb: LIQUID, type code %, sha256 e48b844bab28b6a1…

19: PHASE LIQUID:L % 1 1 !
20: CONST LIQUID:L : TA W : !

TaW-22Zha.tdb: LIQUID, type code %, sha256 3daec7c0661909a7…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : TA W : !

TaW-95Fer.tdb: LIQUID, type code %, sha256 50f38ebf2b2eefbf…

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

Example references (3 of 3; assessments first):

doi:10.1016/j.ijrmhm.2022.105780 Enkuan Zhang, Ying Tang, Mingwen Wen, Abdulmonem Obaied, Irina Roslyakova, Lijun Zhang, On phase stability of Mo-Nb-Ta-W refractory high entropy alloys, International Journal of Refractory Metals and Hard Materials 103, 105780 (2022).
assessment that models this phase
doi:10.1016/S0364-5916(01)00061-X L. Kaufman, P.E.A. Turchi, W. Huang, Z.-K. Liu, Calphad, 25, 419-33(2001).
assessment that models this phase
doi:10.3139/146.111125 C. Guo, C. Li, S. Shang, Z. Du, Thermodynamic description of the Ta–W–Zr system, Int. J. Mater. Res. 105 (11) (2014) 1048–1056.
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}
}