Al–Hf system

55 accepted literature values from 1 paper(s) (experimental 19, model 36); 1 calculated phase diagram(s).

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (12) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	19
model	36

Accepted values by property group
Property group	Values
invariant reaction	29
formation	26

Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
AlHf-02Wan.tdb	T. Wang, Z. Jin, J.-C. Zhao, J. Phase Equilib., 23, 416-23(2002). doi:10.1361/105497102770331361	`5a64ef43c1f8c593139372013ed422d67782199ea4f2edfa5f0f0c72c3d40394`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
AlHf-02Wan.tdb	1911.13	AL3HF2 (x(Hf) 0.4) + LIQUID (x(Hf) 0.42681) + ALHF_B33 (x(Hf) 0.5)
AlHf-02Wan.tdb	1911.13	AL3HF2 (x(Hf) 0.4) + LIQUID (x(Hf) 0.42696) + ALHF_B33 (x(Hf) 0.5)
AlHf-02Wan.tdb	1878.71	AL2HF_C14 (x(Hf) 0.33333) + LIQUID (x(Hf) 0.35303) + AL3HF2 (x(Hf) 0.4)
AlHf-02Wan.tdb	1878.71	AL2HF_C14 (x(Hf) 0.33333) + LIQUID (x(Hf) 0.35329) + AL3HF2 (x(Hf) 0.4)
AlHf-02Wan.tdb	1841.57	AL3HF_D022 (x(Hf) 0.25) + LIQUID (x(Hf) 0.28281) + AL2HF_C14 (x(Hf) 0.33333)
AlHf-02Wan.tdb	1841.57	AL3HF_D022 (x(Hf) 0.25) + LIQUID (x(Hf) 0.2826) + AL2HF_C14 (x(Hf) 0.33333)
AlHf-02Wan.tdb	1838.59	ALHF_B33 (x(Hf) 0.5) + LIQUID (x(Hf) 0.58993) + AL2HF3 (x(Hf) 0.6)
AlHf-02Wan.tdb	1838.58	ALHF_B33 (x(Hf) 0.5) + LIQUID (x(Hf) 0.59021) + AL2HF3 (x(Hf) 0.6)
AlHf-02Wan.tdb	1800.53	AL2HF3 (x(Hf) 0.6) + LIQUID (x(Hf) 0.65251) + BCC_A2 (x(Hf) 0.68997)
AlHf-02Wan.tdb	1800.53	AL2HF3 (x(Hf) 0.6) + LIQUID (x(Hf) 0.65257) + BCC_A2 (x(Hf) 0.69003)
AlHf-02Wan.tdb	1726.93	AL2HF3 (x(Hf) 0.6) + BCC_A2 (x(Hf) 0.71882) + HCP_A3 (x(Hf) 0.72776)
AlHf-02Wan.tdb	1726.93	AL2HF3 (x(Hf) 0.6) + BCC_A2 (x(Hf) 0.71897) + HCP_A3 (x(Hf) 0.72791)
AlHf-02Wan.tdb	1673.17	ALHF_B33 (x(Hf) 0.5) + AL3HF4 (x(Hf) 0.57143) + AL2HF3 (x(Hf) 0.6)
AlHf-02Wan.tdb	1473.27	AL2HF3 (x(Hf) 0.6) + ALHF2_C16 (x(Hf) 0.66667) + HCP_A3 (x(Hf) 0.802)
AlHf-02Wan.tdb	1473.27	AL2HF3 (x(Hf) 0.6) + ALHF2_C16 (x(Hf) 0.66667) + HCP_A3 (x(Hf) 0.80209)
AlHf-02Wan.tdb	1473.27	AL2HF3 (x(Hf) 0.6) + ALHF2_C16 (x(Hf) 0.66667) + HCP_A3 (x(Hf) 0.80207)
AlHf-02Wan.tdb	1473.27	AL2HF3 (x(Hf) 0.6) + ALHF2_C16 (x(Hf) 0.66667) + HCP_A3 (x(Hf) 0.8021)
AlHf-02Wan.tdb	934.73	LIQUID (x(Hf) 6.200e-4) + FCC_A1 (x(Hf) 0.00243) + AL3HF_D022 (x(Hf) 0.25)
AlHf-02Wan.tdb	934.73	LIQUID (x(Hf) 6.000e-4) + FCC_A1 (x(Hf) 0.00237) + AL3HF_D022 (x(Hf) 0.25)
AlHf-02Wan.tdb	923.08	FCC_A1 (x(Hf) 0.00219) + AL3HF_D023 (x(Hf) 0.25) + AL3HF_D022 (x(Hf) 0.25)
AlHf-02Wan.tdb	923.08	AL3HF_D022 (x(Hf) 0.25) + AL3HF_D023 (x(Hf) 0.25) + AL2HF_C14 (x(Hf) 0.33333)
AlHf-02Wan.tdb	923.08	FCC_A1 (x(Hf) 0.00219) + AL3HF_D023 (x(Hf) 0.25) + AL3HF_D022 (x(Hf) 0.25)
AlHf-02Wan.tdb	923.08	FCC_A1 (x(Hf) 0.00219) + AL3HF_D022 (x(Hf) 0.25) + AL3HF_D023 (x(Hf) 0.25)

Convex hulls: Materials Project DFT hull · OQMD DFT hull

Invariant reactions (literature)

Invariant reactions reported in the literature for the Al–Hf system (29)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
2073	congruent melting: L ↔ HfAl	HfAl: Al 0.5	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 13 report
2034	congruent melting: L ↔ HfAl	HfAl: Al 0.5	model	[1] Wang 2002	Table 1, p. 2, row 14 report
1929	congruent melting: L ↔ Hf2Al3	Hf2Al3: Al 0.6	model	[1] Wang 2002	Table 1, p. 2, row 17 report
1923	congruent melting: L ↔ HFAl2	HFAl2: Al 0.667	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 20 report
1913	L + HfAl ↔ Hf2Al3	HfAl: Al 0.5; Hf2Al3: Al 0.6	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 15 report
1911	L ↔ HfAl + Hf2Al3	L: Al 0.573; HfAl: Al 0.5; Hf2Al3: Al 0.6	model	[1] Wang 2002	Table 1, p. 2, row 16 report
1886	congruent melting: L ↔ HFAl2	HFAl2: Al 0.667	model	[1] Wang 2002	Table 1, p. 2, row 21 report
1879	L ↔ Hf2Al3 + HfAl2	L: Al 0.647; Hf2Al3: Al 0.6; HfAl2: Al 0.667	model	[1] Wang 2002	Table 1, p. 2, row 19 report
1863	congruent melting: L ↔ HfAl3(β)	HfAl3(β): Al 0.75	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 24 report
1863	congruent melting: L ↔ Hf3Al2	Hf3Al2: Al 0.4	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 7 report
1856	congruent melting: L ↔ HfAl3(β)	HfAl3(β): Al 0.75	model	[1] Wang 2002	Table 1, p. 2, row 25 report
1842	L ↔ HfAl2 + HfAl3(β)	L: Al 0.717; HfAl2: Al 0.667; HfAl3(β): Al 0.75	model	[1] Wang 2002	Table 1, p. 2, row 23 report
1840	congruent melting: L ↔ Hf3Al2	Hf3Al2: Al 0.4	model	[1] Wang 2002	Table 1, p. 2, row 8 report
1839	L ↔ Hf3Al2 + HfAl	L: Al 0.41; Hf3Al2: Al 0.4; HfAl: Al 0.5	model	[1] Wang 2002	Table 1, p. 2, row 10 report
1823	L ↔ Hf3Al2 + HfAl	L: Al 0.45; Hf3Al2: Al 0.4; HfAl: Al 0.5	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 9 report
1813	L ↔ HfAl2 + HfAl3(β)	HfAl2: Al 0.667; HfAl3(β): Al 0.75	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 22 report
1803	L ↔ bcc + Hf3Al2	L: Al 0.36; bcc: Al 0.33; Hf3Al2: Al 0.4	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 5 report
1801	L ↔ bcc + Hf3Al2	L: Al 0.347; bcc: Al 0.31; Hf3Al2: Al 0.4	model	[1] Wang 2002	Table 1, p. 2, row 6 report
1768	L ↔ Hf2Al3 + HfAl2	Hf2Al3: Al 0.6; HfAl2: Al 0.667	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 18 report
1727	bcc ↔ cph + Hf3Al2	bcc: Al 0.281; cph: Al 0.272; Hf3Al2: Al 0.4	model	[1] Wang 2002	Table 1, p. 2, row 2 report
1723	bcc ↔ cph + Hf3Al2	bcc: Al 0.3; cph: Al 0.27; Hf3Al2: Al 0.4	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 1 report
1673	Hf3Al2 + HfAl ↔ Hf4Al3	Hf3Al2: Al 0.4; HfAl: Al 0.5; Hf4Al3: Al 0.429	model	[1] Wang 2002	Table 1, p. 2, row 12 report
1473	cph + Hf3Al2 ↔ Hf2Al	cph: Al 0.198; Hf3Al2: Al 0.4; Hf2Al: Al 0.333	model	[1] Wang 2002	Table 1, p. 2, row 4 report
1273	cph + Hf3Al2 ↔ Hf2Al	Hf3Al2: Al 0.4, Hf 0.6; Hf2Al: Al 0.333333, Hf 0.666667	experimental	[1] Wang 2002 cites Tsyganova 1970	Table 1, p. 2, row 3 report
1223	Hf3Al2 + HfAl ↔ Hf4Al3	Hf3Al2: Al 0.4; HfAl: Al 0.5; Hf4Al3: Al 0.429	experimental	[1] Wang 2002 cites Potzschke 1962	Table 1, p. 2, row 11 report
935.3	HfAl3(β) + L ↔ fcc	HfAl3(β): Al 0.75; L: Al 0.9993; fcc: Al 0.9981	experimental	[1] Wang 2002 cites Rath 1960	Table 1, p. 2, row 26 report
934.8	HfAl3(β) + L ↔ fcc	HfAl3(β): Al 0.75; L: Al 0.9994; fcc: Al 0.9976	model	[1] Wang 2002	Table 1, p. 2, row 27 report
923	polymorphic: HfAl3(β) ↔ HfAl3(α)	HfAl3(β): Al 0.75	experimental	[1] Wang 2002 cites Potzschke 1962	Table 1, p. 2, row 28 report
923	polymorphic: HfAl3(β) ↔ HfAl3(α)	HfAl3(β): Al 0.75	model	[1] Wang 2002	Table 1, p. 2, row 29 report

Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from dft_parity.json.

Enthalpies of formation, Al–Hf system (26)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
Hf2Al	AlHf2	-41.2 kJ/mol-atom		model	-25.526 (mp-aaaaasxg)	-25.508 (oqmd-19400)	[1] Wang 2002	Table 2, p. 3, row 3 report
Hf2Al	AlHf2	-41 kJ/mol-atom		model	-25.526 (mp-aaaaasxg)	-25.508 (oqmd-19400)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 1 report
Hf2Al	AlHf2	-38.9 kJ/mol-atom		model	-25.526 (mp-aaaaasxg)	-25.508 (oqmd-19400)	[1] Wang 2002	Table 2, p. 3, row 2 report
Hf2Al3	Al3Hf2	-49.2 kJ/mol-atom		model	-41.152 (mp-aaaaabgo)	-41.101 (oqmd-19010)	[1] Wang 2002	Table 2, p. 3, row 16 report
Hf2Al3	Al3Hf2	-47.5 kJ/mol-atom		model	-41.152 (mp-aaaaabgo)	-41.101 (oqmd-19010)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 15 report
Hf2Al3	Al3Hf2	-42.9 kJ/mol-atom		model	-41.152 (mp-aaaaabgo)	-41.101 (oqmd-19010)	[1] Wang 2002	Table 2, p. 3, row 17 report
Hf2Al3	Al3Hf2	-40.8 kJ/mol-atom	298.15	experimental	-41.152 (mp-aaaaabgo)	-41.101 (oqmd-19010)	[1] Wang 2002 cites Balducci 1995 doi	Table 2, p. 3, row 14 report
Hf3Al2	Al2Hf3	-48.9 kJ/mol-atom		model	-31.894 (mp-aaaaamnm)	-31.931 (oqmd-11338)	[1] Wang 2002	Table 2, p. 3, row 6 report
Hf3Al2	Al2Hf3	-45 kJ/mol-atom		model	-31.894 (mp-aaaaamnm)	-31.931 (oqmd-11338)	[1] Wang 2002	Table 2, p. 3, row 5 report
Hf3Al2	Al2Hf3	-43.5 kJ/mol-atom		model	-31.894 (mp-aaaaamnm)	-31.931 (oqmd-11338)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 4 report
Hf4Al3	Al3Hf4	-47.9 kJ/mol-atom		model	-38 (mp-aaacgipr)	-37.785 (oqmd-27836)	[1] Wang 2002	Table 2, p. 3, row 9 report
Hf4Al3	Al3Hf4	-47.1 kJ/mol-atom		model	-38 (mp-aaacgipr)	-37.785 (oqmd-27836)	[1] Wang 2002	Table 2, p. 3, row 8 report
Hf4Al3	Al3Hf4	-44.4 kJ/mol-atom		model	-38 (mp-aaacgipr)	-37.785 (oqmd-27836)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 7 report
HfAl	AlHf	-50.3 kJ/mol-atom		model	-38.759 (mp-aaaaaajp)	-38.774 (oqmd-18706)	[1] Wang 2002	Table 2, p. 3, row 12 report
HfAl	AlHf	-46.3 kJ/mol-atom		model	-38.759 (mp-aaaaaajp)	-38.774 (oqmd-18706)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 11 report
HfAl	AlHf	-45.2 kJ/mol-atom		model	-38.759 (mp-aaaaaajp)	-38.774 (oqmd-18706)	[1] Wang 2002	Table 2, p. 3, row 13 report
HfAl	AlHf	-39.9 kJ/mol-atom	298.15	experimental	-38.759 (mp-aaaaaajp)	-38.774 (oqmd-18706)	[1] Wang 2002 cites Meschel 1993 doi	Table 2, p. 3, row 10 report
HfAl2	Al2Hf	-48.3 kJ/mol-atom		model	-42.633 (mp-aaaaassv)	-42.842 (oqmd-19094)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 19 report
HfAl2	Al2Hf	-44.7 kJ/mol-atom		model	-42.633 (mp-aaaaassv)	-42.842 (oqmd-19094)	[1] Wang 2002	Table 2, p. 3, row 20 report
HfAl2	Al2Hf	-43.8 kJ/mol-atom	298.15	experimental	-42.633 (mp-aaaaassv)	-42.842 (oqmd-19094)	[1] Wang 2002 cites Meschel 1993 doi	Table 2, p. 3, row 18 report
HfAl2	Al2Hf	-41.7 kJ/mol-atom		model	-42.633 (mp-aaaaassv)	-42.842 (oqmd-19094)	[1] Wang 2002	Table 2, p. 3, row 21 report
HfAl3	Al3Hf	-44.7 kJ/mol-atom	298.15	experimental	-38.14 (mp-aaabgjhu)	-38.236 (oqmd-19074)	[1] Wang 2002 cites Balducci 1995 doi	Table 2, p. 3, row 23 report
HfAl3	Al3Hf	-41.8 kJ/mol-atom		model	-38.14 (mp-aaabgjhu)	-38.236 (oqmd-19074)	[1] Wang 2002 cites ref. 1975Kao	Table 2, p. 3, row 24 report
HfAl3	Al3Hf	-41.1 kJ/mol-atom		model	-38.14 (mp-aaabgjhu)	-38.236 (oqmd-19074)	[1] Wang 2002	Table 2, p. 3, row 26 report
HfAl3	Al3Hf	-40.6 kJ/mol-atom	298.15	experimental	-38.14 (mp-aaabgjhu)	-38.236 (oqmd-19074)	[1] Wang 2002 cites Meschel 1993 doi	Table 2, p. 3, row 22 report
HfAl3	Al3Hf	-35.6 kJ/mol-atom		model	-38.14 (mp-aaabgjhu)	-38.236 (oqmd-19074)	[1] Wang 2002	Table 2, p. 3, row 25 report

Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

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

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735859
R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735891
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 the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); 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). 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_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@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}
}