About ORCHID
Open Repository for CALPHAD Hypotheses, Intelligence, and Discovery
Mission
ORCHID is an open, provenance-tracked collection of CALPHAD data: thermodynamic databases (TDB files) and the evidence behind them. Every value records where it came from, under which licence it may be used, and what kind of evidence it is (experimental, model, first-principles or assessed phase diagram). Evidence classes are kept apart and never averaged. The data are versioned, citable and machine-readable, for people and for AI models alike.
What is in it
Database catalog
Openly available CALPHAD databases with elements, phases, source and licence; the redistributable files for download.
Literature dataset
Invariant reactions, transitions, phase compositions, thermochemical and structural values from published papers, each with its source and the quote or table row behind it.
Data explorer
Search the literature values by element, system, compound, DOI or author.
Phase diagrams
Binary phase diagrams calculated from open TDB files, each linked to the exact file and checksum.
DFT vs experiment
Literature formation enthalpies against Materials Project and OQMD, side by side, never averaged.
Hulls & mixing
DFT and CALPHAD formation-energy hulls and mixing curves on one composition axis.
How it is built
- Readers constrained to quote. Values are read from lawfully held papers by independent machine readers, and each value must come with the verbatim sentence or table row that states it.
- Quote verification. A value is kept only if its quote is found verbatim on one page of the paper and the printed number is inside it; tables are accepted only when independent readers agree.
- Field placement. Every published field (phase, method, reaction, citation, temperature) must be printed in the value's own quote or its immediate context; fields that are not are removed.
- Printed-page sign checks. Minus signs lost by the PDF text layer are checked on the rendered page; values printed without a sign are kept as printed and flagged.
- DFT comparison. Formation enthalpies are paired with the lowest-energy Materials Project and OQMD entries at the same composition, as an independent plausibility check.
Details, counts and the field reference are on the dataset page; every stage, with links to its code, is on How ORCHID is built.
Team
Licensing
- Derived data (values, units, conditions, phases, compositions, evidence classes, citations): CC BY 4.0. Credit ORCHID and the original paper of each value.
- Quotes. Each quote is a short excerpt kept only so that a value can be checked against its source; it remains under the publisher’s copyright and is not relicensed.
- Papers are not redistributed. No PDFs, page images, crops or full text; read the papers at the publisher through the DOI.
- Third-party databases and data keep their own licences, listed in NOTICE and LICENSES. Files we may not redistribute are listed with links to their sources only.
- Site code and catalog: MIT.
Contributing
Found a wrong value, or know a paper we should read? Every value on the data pages has a report link that opens a pre-filled GitHub issue; papers and assessments can be suggested with an issue form, and data are contributed by pull request. Every contribution is checked against its source and credited. See Contribute to ORCHID.
How to cite
If you use ORCHID data, cite the dataset you used, the umbrella record, and the original sources of the data. Release v2026.10 (Version 1) is archived on Zenodo as eight datasets, each with its own DOI.
- 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-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735943
- 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-Assemblages: assessed phase assemblages of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735996
- R. Arróyave, J. Saal, D. Shin, ORCHID ESPEI datasets: literature and database-derived thermodynamic fitting inputs (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735788
- R. Arróyave, J. Saal, D. Shin, ORCHID-Bibliography: papers and typed citation relations (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736021
- 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); G. Kim, S. V. Meschel, P. Nash, W. Chen, Experimental formation enthalpies for intermetallic phases and other inorganic compounds, Scientific Data 4 (2017) 170162, https://doi.org/10.1038/sdata.2017.162; for every diagram used, its original evaluation (citations[role=original_evaluation], DOI where matched) and H. Okamoto, Desk Handbook: Phase Diagrams for Binary Alloys, 2nd ed., ASM International (2010) as the compilation; the original source of every value you use (each dataset's `reference` / `bibtex`, references.bib; index.csv lists the DOIs); the papers themselves when you use their data (doi / citation of each bibliography record).
@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_dft_benchmark_2026,
author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
title = {{ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark}},
version = {2026.10},
publisher = {Zenodo},
year = {2026},
doi = {10.5281/zenodo.23735943},
url = {https://doi.org/10.5281/zenodo.23735943},
note = {Version 1, machine-extracted}
}
@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_assessed_assemblages_2026,
author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
title = {{ORCHID-Assemblages: assessed phase assemblages of binary systems}},
version = {2026.10},
publisher = {Zenodo},
year = {2026},
doi = {10.5281/zenodo.23735996},
url = {https://doi.org/10.5281/zenodo.23735996},
note = {Version 1, machine-extracted}
}
@misc{orchid_espei_2026,
author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
title = {{ORCHID ESPEI datasets: literature and database-derived thermodynamic fitting inputs}},
version = {2026.10},
publisher = {Zenodo},
year = {2026},
doi = {10.5281/zenodo.23735788},
url = {https://doi.org/10.5281/zenodo.23735788},
note = {Version 1, machine-extracted}
}
@misc{orchid_bibliography_2026,
author = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
title = {{ORCHID-Bibliography: papers and typed citation relations}},
version = {2026.10},
publisher = {Zenodo},
year = {2026},
doi = {10.5281/zenodo.23736021},
url = {https://doi.org/10.5281/zenodo.23736021},
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}
}
Machine-readable: CITATION.cff · Croissant metadata · llms.txt.
Contact
Code and issues: github.com/orchid-calphad.
Software and data citations
These credits describe the ORCHID project and its examples. Cite the papers and software used in your analysis, together with the ORCHID release and original source of each observation. The list does not imply that every dataset was generated with every package. Preserve the versions and commit hashes recorded by each example; a repository link is not a reproducibility pin. Materials Project and OQMD energies retain separate references.
- pycalphad: Thermodynamic calculations and phase equilibria. R. Otis and Z.-K. Liu (2017), pycalphad: CALPHAD-based Computational Thermodynamics in Python (10.5334/jors.140). Repository.
- ESPEI: Thermodynamic parameter fitting and uncertainty quantification. B. Bocklund et al. (2019), ESPEI for efficient thermodynamic database development, modification, and uncertainty quantification: application to Cu–Mg (10.1557/mrc.2019.59). Repository.
- PhaseForge: MLIP-informed CALPHAD construction in the examples. S. Zhu, D. Sarıtürk, and R. Arróyave (2025), Machine learning potentials for alloys: a detailed workflow to predict phase diagrams and benchmark accuracy (10.1038/s41524-025-01814-z). Repository; archived software.
- PhaseForge+: Construction and experimental tuning of CALPHAD models in the examples; repository name PhaseForgePlus. C. Kunselman, S. Zhu, D. Sarıtürk, and R. Arróyave (2025), Construction and Tuning of CALPHAD Models Using Machine-Learned Interatomic Potentials and Experimental Data: A Case Study of the Pt–W System (10.1007/s11669-025-01222-2). Repository; archived software.
- Materials Project: DFT structures and energies; repository link is the API client, not the database itself. A. Jain et al. (2013), Commentary: The Materials Project: A materials genome approach to accelerating materials innovation (10.1063/1.4812323). Repository; data resource.
- OQMD: DFT structures and energies; qmpy is the supporting software. J. E. Saal et al. (2013), Materials Design and Discovery with High-Throughput Density Functional Theory: The Open Quantum Materials Database (OQMD) (10.1007/s11837-013-0755-4); S. Kirklin et al. (2015), The Open Quantum Materials Database (OQMD): assessing the accuracy of DFT formation energies (10.1038/npjcompumats.2015.10). Repository; data resource.
The same credits as a file: CITATIONS.md (also CITATIONS.json).
Funding
This work was supported by the U.S. National Science Foundation under awards OAC-2608825 and 2534344.