Al–Hf phases

12 phases (tier A 8, tier B 1, tier C 2, liquid 1); 12 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 · Al–Hf system page · Markdown · field reference

Phases of the Al–Hf system (12)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
AL2HF_C14 phase:al-hf:al2hf-c14	MgZn2 · C14 · hP12 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1886.29 K, x(Hf) 0.33333–0.33333	6	1
AL2HF3 phase:al-hf:al2hf3	Al2Zr3 · tP20 · P4_2/mnm (136)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1839.79 K, x(Hf) 0.6–0.6	12	1
AL3HF_D022 phase:al-hf:al3hf-d022	Al3Ti · D0_22 · tI8 · I4/mmm (139)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 923.08–1856.15 K, x(Hf) 0.25–0.25	0	1
AL3HF_D023 phase:al-hf:al3hf-d023	Al3Zr · D0_23 · tI16 · I4/mmm (139)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–923.08 K, x(Hf) 0.25–0.25	0	1
AL3HF2 phase:al-hf:al3hf2	Al3Zr2 · oF40 · Fdd2 (43)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1928.71 K, x(Hf) 0.4–0.4	5	1
AL3HF4 phase:al-hf:al3hf4	Al3Zr4 · hP7 · P6/mmm (191)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–1673.17 K, x(Hf) 0.57143–0.57143	2	1
ALHF_B33 phase:al-hf:alhf-b33	CrB · B33 · oC8 · Cmcm (63)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2033.63 K, x(Hf) 0.5–0.5	8	1
ALHF2_C16 phase:al-hf:alhf2-c16	Al2Cu · C16 · tI12 · I4/mcm (140)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1473.27 K, x(Hf) 0.66667–0.66667	2	1
BCC_A2 phase:al-hf:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 1726.93–3999.75 K, x(Hf) 0.68997–1	4	1
FCC_A1 phase:al-hf:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–934.73 K, x(Hf) 0–0.00243	2	1
HCP_A3 phase:al-hf:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2031.93 K, x(Hf) 0.72776–1	4	1
LIQUID phase:al-hf:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 933.48–4000 K, x(Hf) 0–1	21	1

AL2HF_C14 (Al–Hf)

Id: phase:al-hf:al2hf-c14; status assigned
Structure: MgZn2 · C14 · hP12 · P6_3/mmc (194); type st:c14-mgzn2-hp12; tier A: standard phase name; confidence high
Caveat: DFT agrees: on-hull mp-aaaaassv and oqmd-19094, space group 194
Stoichiometry: Al 0.6667, Hf 0.3333
Stability: stable in 1 of 1 calculated diagram(s): 300–1886.29 K, x(Hf) 0.33333–0.33333
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:al-hf:al2hf-c14
mp: mp:mp-aaaaassv
oqmd: oqmd:oqmd-19094
paper: paper:10.1361/105497102770331361:HFAl2, paper:10.1361/105497102770331361:HfAl2
tdb: tdb:AlHf-02Wan.tdb:AL2HF_C14

TDB models of AL2HF_C14 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL2HF_C14, type code %, sha256 5a64ef43c1f8c593…

54: PHASE AL2HF_C14 % 2 2 1 !
55: CONST AL2HF_C14 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

AL2HF3 (Al–Hf)

Id: phase:al-hf:al2hf3; status assigned
Structure: Al2Zr3 · tP20 · P4_2/mnm (136); type st:al2zr3-tp20; 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
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, Hf 0.6000
Stability: stable in 1 of 1 calculated diagram(s): 300–1839.79 K, x(Hf) 0.6–0.6
Literature: 12 values (12 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:al2hf3
paper: paper:10.1361/105497102770331361:Hf3Al2
tdb: tdb:AlHf-02Wan.tdb:AL2HF3

TDB models of AL2HF3 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL2HF3, type code %, sha256 5a64ef43c1f8c593…

74: PHASE AL2HF3 % 2 2 3 !
75: CONST AL2HF3 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

AL3HF_D022 (Al–Hf)

Id: phase:al-hf:al3hf-d022; status assigned
Structure: Al3Ti · D0_22 · tI8 · I4/mmm (139); type st:d0-22-al3ti-ti8; tier A: standard phase name; confidence high
Stoichiometry: Al 0.7500, Hf 0.2500
Stability: stable in 1 of 1 calculated diagram(s): 923.08–1856.15 K, x(Hf) 0.25–0.25
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-hf:al3hf-d022
tdb: tdb:AlHf-02Wan.tdb:AL3HF_D022

TDB models of AL3HF_D022 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL3HF_D022, type code %, sha256 5a64ef43c1f8c593…

49: PHASE AL3HF_D022 % 2 3 1 !
50: CONST AL3HF_D022 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase

AL3HF_D023 (Al–Hf)

Id: phase:al-hf:al3hf-d023; status assigned
Structure: Al3Zr · D0_23 · tI16 · I4/mmm (139); type st:d0-23-al3zr-ti16; tier A: standard phase name; confidence high
Stoichiometry: Al 0.7500, Hf 0.2500
Stability: stable in 1 of 1 calculated diagram(s): 300–923.08 K, x(Hf) 0.25–0.25
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-hf:al3hf-d023
tdb: tdb:AlHf-02Wan.tdb:AL3HF_D023

TDB models of AL3HF_D023 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL3HF_D023, type code %, sha256 5a64ef43c1f8c593…

44: PHASE AL3HF_D023 % 2 3 1 !
45: CONST AL3HF_D023 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase

AL3HF2 (Al–Hf)

Id: phase:al-hf:al3hf2; status assigned
Structure: Al3Zr2 · oF40 · Fdd2 (43); type st:al3zr2-of40; 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
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 0.6000, Hf 0.4000
Stability: stable in 1 of 1 calculated diagram(s): 300–1928.71 K, x(Hf) 0.4–0.4
Literature: 5 values (5 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:al3hf2
paper: paper:10.1361/105497102770331361:Hf2Al3
tdb: tdb:AlHf-02Wan.tdb:AL3HF2

TDB models of AL3HF2 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL3HF2, type code %, sha256 5a64ef43c1f8c593…

59: PHASE AL3HF2 % 2 3 2 !
60: CONST AL3HF2 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

AL3HF4 (Al–Hf)

Id: phase:al-hf:al3hf4; status assigned
Structure: Al3Zr4 · hP7 · P6/mmm (191); type st:al3zr4-hp7; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: Al 0.4286, Hf 0.5714
Stability: stable in 1 of 1 calculated diagram(s): 300–1673.17 K, x(Hf) 0.57143–0.57143
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:al-hf:al3hf4
mp: mp:mp-aaacgipr
oqmd: oqmd:oqmd-27836
paper: paper:10.1361/105497102770331361:Hf4Al3
tdb: tdb:AlHf-02Wan.tdb:AL3HF4

TDB models of AL3HF4 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: AL3HF4, type code %, sha256 5a64ef43c1f8c593…

69: PHASE AL3HF4 % 2 3 4 !
70: CONST AL3HF4 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

ALHF_B33 (Al–Hf)

Id: phase:al-hf:alhf-b33; status assigned
Structure: CrB · B33 · oC8 · Cmcm (63); type st:b33-crb-oc8; tier A: standard phase name; confidence high
Stoichiometry: Al 0.5000, Hf 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–2033.63 K, x(Hf) 0.5–0.5
Literature: 8 values (8 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:alhf-b33
paper: paper:10.1361/105497102770331361:HfAl
tdb: tdb:AlHf-02Wan.tdb:ALHF_B33

TDB models of ALHF_B33 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: ALHF_B33, type code %, sha256 5a64ef43c1f8c593…

64: PHASE ALHF_B33 % 2 1 1 !
65: CONST ALHF_B33 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

ALHF2_C16 (Al–Hf)

Id: phase:al-hf:alhf2-c16; status assigned
Structure: Al2Cu · C16 · tI12 · I4/mcm (140); type st:c16-al2cu-ti12; tier A: standard phase name; confidence high
Stoichiometry: Al 0.3333, Hf 0.6667
Stability: stable in 1 of 1 calculated diagram(s): 300–1473.27 K, x(Hf) 0.66667–0.66667
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:alhf2-c16
paper: paper:10.1361/105497102770331361:Hf2Al
tdb: tdb:AlHf-02Wan.tdb:ALHF2_C16

TDB models of ALHF2_C16 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: ALHF2_C16, type code %, sha256 5a64ef43c1f8c593…

79: PHASE ALHF2_C16 % 2 1 2 !
80: CONST ALHF2_C16 : AL : HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

BCC_A2 (Al–Hf)

Id: phase:al-hf: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 1 of 1 calculated diagram(s): 1726.93–3999.75 K, x(Hf) 0.68997–1
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:bcc-a2
paper: paper:10.1361/105497102770331361:bcc
tdb: tdb:AlHf-02Wan.tdb:BCC_A2

TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: BCC_A2, type code %B, sha256 5a64ef43c1f8c593…

34: PHASE BCC_A2 %B 2 1 3 !
35: CONST BCC_A2 : AL HF% : VA : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

FCC_A1 (Al–Hf)

Id: phase:al-hf: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 1 of 1 calculated diagram(s): 300–934.73 K, x(Hf) 0–0.00243
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:fcc-a1
paper: paper:10.1361/105497102770331361:fcc
tdb: tdb:AlHf-02Wan.tdb:FCC_A1

TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: FCC_A1, type code %A, sha256 5a64ef43c1f8c593…

29: PHASE FCC_A1 %A 2 1 1 !
30: CONST FCC_A1 : AL% HF : VA : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

HCP_A3 (Al–Hf)

Id: phase:al-hf: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 1 calculated diagram(s): 300–2031.93 K, x(Hf) 0.72776–1
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:hcp-a3
paper: paper:10.1361/105497102770331361:cph
tdb: tdb:AlHf-02Wan.tdb:HCP_A3

TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

AlHf-02Wan.tdb: HCP_A3, type code %A, sha256 5a64ef43c1f8c593…

39: PHASE HCP_A3 %A 2 1 0.5 !
40: CONST HCP_A3 : AL HF% : VA : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports values for this phase

LIQUID (Al–Hf)

Id: phase:al-hf:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 933.48–4000 K, x(Hf) 0–1
Literature: 21 values (21 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:al-hf:liquid
paper: paper:10.1361/105497102770331361:L
tdb: tdb:AlHf-02Wan.tdb:LIQUID

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

AlHf-02Wan.tdb: LIQUID, type code %, sha256 5a64ef43c1f8c593…

24: PHASE LIQUID:L % 1 1 !
25: CONST LIQUID:L : AL HF : !

Example references (1 of 1; assessments first):

doi:10.1361/105497102770331361 Tao Wang, Zhanpeng Jin, Ji-Cheng Zhao, Thermodynamic assessment of the Al-Hf binary system, JPE 23, 416-423 (2002).
assessment that models this phase; reports 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). 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}
}