Al–Si 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 · Al–Si system page · Markdown · field reference

Phases of the Al–Si system (5)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
DIAMOND_A4 phase:al-si:a4-diamond	C (diamond) · A4 · cF8 · Fd-3m (227)	tier A: standard phase name	stable in 5 of 5 calculated diagram(s): 300–1687 K, x(Si) 0.9996–1	0	6
BCC_A2 phase:al-si:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 5 calculated diagram(s)	0	5
FCC_A1 phase:al-si:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 5 of 5 calculated diagram(s): 300–936.34 K, x(Si) 0–0.02319	0	6
HCP_A3 phase:al-si:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 5 calculated diagram(s)	0	6
LIQUID phase:al-si:liquid	liquid	liquid	stable in 5 of 5 calculated diagram(s): 850.09–2500 K, x(Si) 0–1	1	6

DIAMOND_A4 (Al–Si)

Id: phase:al-si:a4-diamond; status assigned
Structure: C (diamond) · A4 · cF8 · Fd-3m (227); type st:a4-c-diamond-cf8; tier A: standard phase name; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 300–1687 K, x(Si) 0.9996–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:al-si:a4-diamond
tdb: tdb:AlSi-12Tan.tdb:DIAMOND_A4, tdb:AlSi-14Lia.tdb:DIAMOND_A4, tdb:AlSi-24Zob-3g.tdb:DIAMOND_A4, tdb:AlSi-86Mey.tdb:DIAMOND_A4, tdb:AlSi-96Jac.tdb:DIAMOND_A4, tdb:AlSi-97Feu-LB.tdb:DIAMOND_A4

TDB models of DIAMOND_A4 (6): PHASE and CONSTITUENT statements as written

AlSi-12Tan.tdb: DIAMOND_A4, type code %, sha256 21db02512088b4f4…

45: PHASE DIAMOND_A4 % 1 1 !
46: CONST DIAMOND_A4 : SI : !

AlSi-14Lia.tdb: DIAMOND_A4, type code %, sha256 256542a28352f756…

43: PHASE DIAMOND_A4 % 1 1 !
44: CONST DIAMOND_A4 : AL SI% : !

AlSi-24Zob-3g.tdb: DIAMOND_A4, type code %, sha256 b0c946d2832b3267…

41: PHASE DIAMOND_A4 % 1 1 !
42: CONST DIAMOND_A4 : SI : !

AlSi-86Mey.tdb: DIAMOND_A4, type code %, sha256 ff4e72f4da77273d…

45: PHASE DIAMOND_A4 % 1 1 !
46: CONST DIAMOND_A4 : AL SI% : !

AlSi-96Jac.tdb: DIAMOND_A4, type code %, sha256 2f8447bac48ae55e…

47: PHASE DIAMOND_A4 % 1 1 !
48: CONST DIAMOND_A4 : AL SI% : !

AlSi-97Feu-LB.tdb: DIAMOND_A4, type code %, sha256 c8b80517b0495878…

44: PHASE DIAMOND_A4 % 1 1 !
45: CONST DIAMOND_A4 : AL SI% : !

Example references (5 of 5; assessments first):

doi:10.1016/j.actamat.2014.02.042 Song-Mao Liang, Rainer Schmid-Fetzer, Phosphorus in Al–Si cast alloys: Thermodynamic prediction of the AlP and eutectic (Si) solidification sequence validated by microstructure and nucleation undercooling data, Acta Materialia 72, 41-56 (2014).
assessment that models this phase
doi:10.1016/j.calphad.2024.102742 O. Zobac, A. Kroupa, A. Dinsdale, Calphad, 87, 102742(2024).
assessment that models this phase
doi:10.1016/j.tca.2011.10.017 Ying Tang, Yong Du, Lijun Zhang, Xiaoming Yuan, George Kaptay, Thermodynamic description of the Al–Mg–Si system using a new formulation for the temperature dependence of the excess Gibbs energy, Thermochimica Acta 527, 131-142 (2012).
assessment that models this phase
doi:10.1016/S0364-5916(96)00033-8 M.H.G. Jacobs, P.J. Spencer, Calphad, 20, 307-20(1996).
assessment that models this phase
doi:10.1016/S0925-8388(96)02655-2 H. Feufel, T. Goedecke, H.L. Lukas, F. Aldinger, J. Alloys Compd., 247, 31-42(1997).
assessment that models this phase

BCC_A2 (Al–Si)

Id: phase:al-si:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: not stable in 5 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:al-si:bcc-a2
tdb: tdb:AlSi-12Tan.tdb:BCC_A2, tdb:AlSi-14Lia.tdb:BCC_A2, tdb:AlSi-86Mey.tdb:BCC_A2, tdb:AlSi-96Jac.tdb:BCC_A2, tdb:AlSi-97Feu-LB.tdb:BCC_A2

TDB models of BCC_A2 (5): PHASE and CONSTITUENT statements as written

AlSi-12Tan.tdb: BCC_A2, type code %B, sha256 21db02512088b4f4…

35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : AL SI : VA : !

AlSi-14Lia.tdb: BCC_A2, type code %B, sha256 256542a28352f756…

33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : AL SI : VA : !

AlSi-86Mey.tdb: BCC_A2, type code %B, sha256 ff4e72f4da77273d…

35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : AL SI : VA : !

AlSi-96Jac.tdb: BCC_A2, type code %B, sha256 2f8447bac48ae55e…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : AL SI : VA : !

AlSi-97Feu-LB.tdb: BCC_A2, type code %B, sha256 c8b80517b0495878…

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

Example references (4 of 4; assessments first):

doi:10.1016/j.actamat.2014.02.042 Song-Mao Liang, Rainer Schmid-Fetzer, Phosphorus in Al–Si cast alloys: Thermodynamic prediction of the AlP and eutectic (Si) solidification sequence validated by microstructure and nucleation undercooling data, Acta Materialia 72, 41-56 (2014).
assessment that models this phase
doi:10.1016/j.tca.2011.10.017 Ying Tang, Yong Du, Lijun Zhang, Xiaoming Yuan, George Kaptay, Thermodynamic description of the Al–Mg–Si system using a new formulation for the temperature dependence of the excess Gibbs energy, Thermochimica Acta 527, 131-142 (2012).
assessment that models this phase
doi:10.1016/S0364-5916(96)00033-8 M.H.G. Jacobs, P.J. Spencer, Calphad, 20, 307-20(1996).
assessment that models this phase
doi:10.1016/S0925-8388(96)02655-2 H. Feufel, T. Goedecke, H.L. Lukas, F. Aldinger, J. Alloys Compd., 247, 31-42(1997).
assessment that models this phase

FCC_A1 (Al–Si)

Id: phase:al-si: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 5 of 5 calculated diagram(s): 300–936.34 K, x(Si) 0–0.02319
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:al-si:fcc-a1
tdb: tdb:AlSi-12Tan.tdb:FCC_A1, tdb:AlSi-14Lia.tdb:FCC_A1, tdb:AlSi-24Zob-3g.tdb:FCC_A1, tdb:AlSi-86Mey.tdb:FCC_A1, tdb:AlSi-96Jac.tdb:FCC_A1, tdb:AlSi-97Feu-LB.tdb:FCC_A1

TDB models of FCC_A1 (6): PHASE and CONSTITUENT statements as written

AlSi-12Tan.tdb: FCC_A1, type code %A, sha256 21db02512088b4f4…

30: PHASE FCC_A1 %A 2 1 1 !
31: CONST FCC_A1 : AL SI : VA : !

AlSi-14Lia.tdb: FCC_A1, type code %A, sha256 256542a28352f756…

28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : AL SI : VA : !

AlSi-24Zob-3g.tdb: FCC_A1, type code %A, sha256 b0c946d2832b3267…

26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : AL% SI : VA : !

AlSi-86Mey.tdb: FCC_A1, type code %A, sha256 ff4e72f4da77273d…

30: PHASE FCC_A1 %A 2 1 1 !
31: CONST FCC_A1 : AL SI : VA : !

AlSi-96Jac.tdb: FCC_A1, type code %A, sha256 2f8447bac48ae55e…

32: PHASE FCC_A1 %A 2 1 1 !
33: CONST FCC_A1 : AL SI : VA : !

AlSi-97Feu-LB.tdb: FCC_A1, type code %A, sha256 c8b80517b0495878…

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

Example references (5 of 5; assessments first):

doi:10.1016/j.actamat.2014.02.042 Song-Mao Liang, Rainer Schmid-Fetzer, Phosphorus in Al–Si cast alloys: Thermodynamic prediction of the AlP and eutectic (Si) solidification sequence validated by microstructure and nucleation undercooling data, Acta Materialia 72, 41-56 (2014).
assessment that models this phase
doi:10.1016/j.calphad.2024.102742 O. Zobac, A. Kroupa, A. Dinsdale, Calphad, 87, 102742(2024).
assessment that models this phase
doi:10.1016/j.tca.2011.10.017 Ying Tang, Yong Du, Lijun Zhang, Xiaoming Yuan, George Kaptay, Thermodynamic description of the Al–Mg–Si system using a new formulation for the temperature dependence of the excess Gibbs energy, Thermochimica Acta 527, 131-142 (2012).
assessment that models this phase
doi:10.1016/S0364-5916(96)00033-8 M.H.G. Jacobs, P.J. Spencer, Calphad, 20, 307-20(1996).
assessment that models this phase
doi:10.1016/S0925-8388(96)02655-2 H. Feufel, T. Goedecke, H.L. Lukas, F. Aldinger, J. Alloys Compd., 247, 31-42(1997).
assessment that models this phase

HCP_A3 (Al–Si)

Id: phase:al-si: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 5 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:al-si:hcp-a3
tdb: tdb:AlSi-12Tan.tdb:HCP_A3, tdb:AlSi-14Lia.tdb:HCP_A3, tdb:AlSi-24Zob-3g.tdb:HCP_A3, tdb:AlSi-86Mey.tdb:HCP_A3, tdb:AlSi-96Jac.tdb:HCP_A3, tdb:AlSi-97Feu-LB.tdb:HCP_A3

TDB models of HCP_A3 (6): PHASE and CONSTITUENT statements as written

AlSi-12Tan.tdb: HCP_A3, type code %A, sha256 21db02512088b4f4…

40: PHASE HCP_A3 %A 2 1 0.5 !
41: CONST HCP_A3 : AL SI : VA : !

AlSi-14Lia.tdb: HCP_A3, type code %A, sha256 256542a28352f756…

38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : AL SI : VA : !

AlSi-24Zob-3g.tdb: HCP_A3, type code %A, sha256 b0c946d2832b3267…

36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : AL SI : VA : !

AlSi-86Mey.tdb: HCP_A3, type code %A, sha256 ff4e72f4da77273d…

40: PHASE HCP_A3 %A 2 1 0.5 !
41: CONST HCP_A3 : AL SI : VA : !

AlSi-96Jac.tdb: HCP_A3, type code %A, sha256 2f8447bac48ae55e…

42: PHASE HCP_A3 %A 2 1 0.5 !
43: CONST HCP_A3 : AL SI : VA : !

AlSi-97Feu-LB.tdb: HCP_A3, type code %A, sha256 c8b80517b0495878…

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

Example references (5 of 5; assessments first):

doi:10.1016/j.actamat.2014.02.042 Song-Mao Liang, Rainer Schmid-Fetzer, Phosphorus in Al–Si cast alloys: Thermodynamic prediction of the AlP and eutectic (Si) solidification sequence validated by microstructure and nucleation undercooling data, Acta Materialia 72, 41-56 (2014).
assessment that models this phase
doi:10.1016/j.calphad.2024.102742 O. Zobac, A. Kroupa, A. Dinsdale, Calphad, 87, 102742(2024).
assessment that models this phase
doi:10.1016/j.tca.2011.10.017 Ying Tang, Yong Du, Lijun Zhang, Xiaoming Yuan, George Kaptay, Thermodynamic description of the Al–Mg–Si system using a new formulation for the temperature dependence of the excess Gibbs energy, Thermochimica Acta 527, 131-142 (2012).
assessment that models this phase
doi:10.1016/S0364-5916(96)00033-8 M.H.G. Jacobs, P.J. Spencer, Calphad, 20, 307-20(1996).
assessment that models this phase
doi:10.1016/S0925-8388(96)02655-2 H. Feufel, T. Goedecke, H.L. Lukas, F. Aldinger, J. Alloys Compd., 247, 31-42(1997).
assessment that models this phase

LIQUID (Al–Si)

Id: phase:al-si:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 850.09–2500 K, x(Si) 0–1
Literature: 1 values (0 accepted) from 1 papers
Interactive: phase registry entry

Names (8): corpus: corpus:phase:al-si:liquid
paper: paper:sha256-85fd53a1a176b694:Liquid
tdb: tdb:AlSi-12Tan.tdb:LIQUID, tdb:AlSi-14Lia.tdb:LIQUID, tdb:AlSi-24Zob-3g.tdb:LIQUID, tdb:AlSi-86Mey.tdb:LIQUID, tdb:AlSi-96Jac.tdb:LIQUID, tdb:AlSi-97Feu-LB.tdb:LIQUID

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

AlSi-12Tan.tdb: LIQUID, type code %, sha256 21db02512088b4f4…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : AL SI : !

AlSi-14Lia.tdb: LIQUID, type code %, sha256 256542a28352f756…

23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : AL SI : !

AlSi-24Zob-3g.tdb: LIQUID, type code %, sha256 b0c946d2832b3267…

21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : AL SI : !

AlSi-86Mey.tdb: LIQUID, type code %, sha256 ff4e72f4da77273d…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : AL SI : !

AlSi-96Jac.tdb: LIQUID, type code %, sha256 2f8447bac48ae55e…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : AL SI : !

AlSi-97Feu-LB.tdb: LIQUID, type code %, sha256 c8b80517b0495878…

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

Example references (5 of 5; assessments first):

doi:10.1016/j.actamat.2014.02.042 Song-Mao Liang, Rainer Schmid-Fetzer, Phosphorus in Al–Si cast alloys: Thermodynamic prediction of the AlP and eutectic (Si) solidification sequence validated by microstructure and nucleation undercooling data, Acta Materialia 72, 41-56 (2014).
assessment that models this phase
doi:10.1016/j.calphad.2024.102742 O. Zobac, A. Kroupa, A. Dinsdale, Calphad, 87, 102742(2024).
assessment that models this phase
doi:10.1016/j.tca.2011.10.017 Ying Tang, Yong Du, Lijun Zhang, Xiaoming Yuan, George Kaptay, Thermodynamic description of the Al–Mg–Si system using a new formulation for the temperature dependence of the excess Gibbs energy, Thermochimica Acta 527, 131-142 (2012).
assessment that models this phase
doi:10.1016/S0364-5916(96)00033-8 M.H.G. Jacobs, P.J. Spencer, Calphad, 20, 307-20(1996).
assessment that models this phase
doi:10.1016/S0925-8388(96)02655-2 H. Feufel, T. Goedecke, H.L. Lukas, F. Aldinger, J. Alloys Compd., 247, 31-42(1997).
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}
}