Software tools for high-throughput CALPHAD from first-principles data

Walle, Axel van de; Sun, Ruoshi; Kadkhodaei, Sara

doi:10.1016/j.calphad.2017.05.005

Cited by 69 publications

(43 citation statements)

References 65 publications

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“…[51] The focus in the present work, though, was to compare the accuracy of sub-lattice models based on "simple and cheap" 0 K DFT-based calculations against qualitative and quantitative experimental trends. It is not surprising that more accurate predictions can be obtained via theoretical models with higher degrees of complexity and costs of computation, [72] but such accurate methods are not practical for materials screening. Nevertheless, we have included an estimate of the errors that can arise in O predictions with and without including the T…”

Section: Discussionmentioning

confidence: 99%

“…Prior examples of sub-lattice models obtained solely from DFT-based data do exist. [72][73][74][75][76][77][78] However, such models have been used primarily for intermetallics and not ionic materials (such as Ce-O and Zr-Ce-O) that usually involve several noncharge-neutral "end-members" (Section 3.1) whose energies are not trivial to obtain theoretically. Note that there is an ongoing effort by the developers of FactSage software [79] in building sublattice models by combining the 0 K DFT data from the Materials Project database [80] with high-throughput computing [81] and/or machine learning to obtain vibrational entropy as a function of temperature (middle panel in Figure 2).…”

Section: Introductionmentioning

confidence: 99%

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A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

Gautam

Stechel

Carter

2020

Advcd Theory and Sims

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Theoretical models that reliably can predict off‐stoichiometry in materials via accurate descriptions of underlying thermodynamics are crucial for energy applications. For example, transition‐metal and rare‐earth oxides that can tolerate a large number of oxygen vacancies, such as CeO2 and doped CeO2, can split water and carbon dioxide via a two‐step, oxide‐based solar thermochemical (STC) cycle. The search for new STC materials with a performance superior to that of state‐of‐the‐art CeO2 can benefit from predictions accurately describing the thermodynamics of oxygen vacancies. The sub‐lattice formalism, a common tool used to fit experimental data and build temperature‐composition phase diagrams, can be useful in this context. Here, sub‐lattice models are derived solely from zero‐temperature quantum mechanics calculations to estimate fairly accurate temperature‐ and oxygen‐partial‐pressure‐dependent off‐stoichiometries in CeO2 and Zr‐doped CeO2. Physical motivations for deriving some of the “excess” sub‐lattice model parameters directly from quantum mechanical calculations, instead of fitting to minimize deviations from experimental and/or theoretical data, are identified. Important limitations and approximations of the approach used are specified and extensions to multi‐cation oxides are also suggested to help identify novel candidates for water and carbon dioxide splitting and related applications.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

Gautam

Stechel

Carter

2020

Advcd Theory and Sims

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“…For completeness, we include the TDB file resulting from our fitting process, although we would not recommend that it be used as is to construct a CAL-PHAD assessment, due to the approximate treatment of the SRO in the fcc and hcp phases. We have attempted to include the fcc and hcp phases as single-sublattice models (with SRO effects properly included via a CVM-based method, [13] ) however the resulting free energies are nearly degenerate with the multi-sublattice descriptions used here and manually correcting the multiple spurious crossing of the corresponding free energies or integrating the singleand multiple-lattice descriptions into a single CEF model would lead to a method that is not really amenable to a high-throughput treatment.…”

Section: Discussionmentioning

confidence: 99%

“…In this work, we use the sqs2tdb tools of the Alloy Theoretic Automated Toolkit (ATAT) [13,14] to generate all structural input files and to construct the Calphad model from the ab initio calculations output. For structures not included in ATAT's pre-generated database of SQS, the ''mcsqs'' code [15] is used to generate suitable SQS with controlled compositions on each sublattice.…”

Section: Methodsmentioning

confidence: 99%

Computational Assessment of Novel Predicted Compounds in Ni-Re Alloy System

Zhu

Walle

2021

J. Phase Equilib. Diffus.

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Ab initio high-throughput efforts are continuously identifying new intermetallic compounds in a wide range of alloy systems that were previously thought to be well-characterized. While such predictions are likely valid near absolute zero, they carry the risk that such phases become unstable at the higher temperature relevant to typical synthesis conditions. We illustrate how this possibility can be rapidly tested by integrating Calphad modeling into the high-throughput loop. As an example, we investigate the Ni-Re system, in which D019 and D1a phases were predicted as possible intermetallic compounds. We confirm that these phases are indeed stable at practical synthesis temperatures and explain how they could have been overlooked in prior assessments.

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“…The state of the art calculation of phase diagrams (Calphad) method [70,71,72,73] allows for the calculation of phase equilibria in multicomponent systems above room temperature at atmospheric pressure, providing that Gibbs free energy functions for all phases from room temperature to the melting point and above can be derived from observed phase equilibria and thermodynamic data. In Calphad assessments, ab initio computational results are treated on the same footing as experimental data.…”

Section: Phase Diagramsmentioning

confidence: 99%

Carbides and Nitrides of Zirconium and Hafnium

et al. 2019

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Among transition metal carbides and nitrides, zirconium, and hafnium compounds are the most stable and have the highest melting temperatures. Here we review published data on phases and phase equilibria in Hf-Zr-C-N-O system, from experiment and ab initio computations with focus on rocksalt Zr and Hf carbides and nitrides, their solid solutions and oxygen solubility limits. The systematic experimental studies on phase equilibria and thermodynamics were performed mainly 40–60 years ago, mostly for binary systems of Zr and Hf with C and N. Since then, synthesis of several oxynitrides was reported in the fluorite-derivative type of structures, of orthorhombic and cubic higher nitrides Zr3N4 and Hf3N4. An ever-increasing stream of data is provided by ab initio computations, and one of the testable predictions is that the rocksalt HfC0.75N0.22 phase would have the highest known melting temperature. Experimental data on melting temperatures of hafnium carbonitrides are absent, but minimum in heat capacity and maximum in hardness were reported for Hf(C,N) solid solutions. New methods, such as electrical pulse heating and laser melting, can fill the gaps in experimental data and validate ab initio predictions.

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Software tools for high-throughput CALPHAD from first-principles data

Cited by 69 publications

References 65 publications

A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

Computational Assessment of Novel Predicted Compounds in Ni-Re Alloy System

Carbides and Nitrides of Zirconium and Hafnium

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