The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study

Perron, Aurélien; Turchi, P. E. A.; Landa, A.; Söderlind, Per; Ravat, B.; Oudot, B.; Delaunay, F.

doi:10.1016/j.jnucmat.2014.12.101

Cited by 17 publications

(18 citation statements)

References 36 publications

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“…Therefore, the use of ab initio energetics during the CALPHAD assessment constrains the optimization process and validates the resulting thermodynamical database, not only from a diagrammatic basis, but also from a reliable energetics basis. Examples of ab-initio-informed CALPHAD assessments for actinide systems can be found in [65,66]. Following the present work, ab initio predictions of specific heat and free energy versus temperature for actinide systems is extremely useful to the CALPHAD community.…”

Section: Calphad Methodsmentioning

confidence: 86%

Ground-State and Thermodynamical Properties of Uranium Mononitride from Anharmonic First-Principles Theory

et al. 2019

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We report on an advanced density-functional theory (DFT) approach for investigating the ground-state and thermodynamical properties of uranium mononitride (UN). The electronic structure for UN at zero temperature is obtained from DFT that utilizes the generalized gradient approximation (GGA) for the electron exchange and correlation functional and includes spin-orbit interaction and an extension with orbital polarization. Thermodynamical properties are computed within the quasi-harmonic approximation in the Debye–Grüneisen model while anharmonicity is captured in the self-consistent ab initio lattice dynamics (SCAILD) scheme. Anharmonic phonons have heretofore never been modeled from first-principles for UN but they turn out to be important. The computed free energy compares well with that of a CALPHAD (CALculation of PHAse Diagrams) assessment of available experimental data.

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Section: Calphad Methodsmentioning

confidence: 86%

Ground-State and Thermodynamical Properties of Uranium Mononitride from Anharmonic First-Principles Theory

et al. 2019

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“…Because the experimental determination of phase diagrams on Plutonium alloys are costly, time-consuming, and challenging, ab initio calculations can provide useful insights into thermodynamic properties (e.g. heat of formation) and inform [36,37] or help to discuss/refine/validate CALPHAD assessments, as it is the case for Pu-Zr. [1,32,33] When ab initio calculations can support constitutive CALPHAD assessments (binary and ternary systems) where data are lacking or missing, more robust predictions can be made for multicomponent actinide systems [38,39] and useful guidance can be provided for well-chosen experiments.…”

Section: Discussionmentioning

confidence: 99%

Experimental and Modeling Review of the Plutonium-Zirconium (Pu-Zr) System: Lost in Translation and Over Time?

Perron

Turchi

2020

J. Phase Equilib. Diffus.

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This article presents a review of the phase equilibria of the Pu-Zr system and discusses the contradictory reports on the experimental phase diagram and misinterpretations that have led to confusion over time. In addition, a review of the few Pu-Zr CALculation of PHAse Diagrams (CALPHAD) assessments is presented with emphasis on the heat of formation of the bcc phase, highlighting a disagreement between CALPHAD and ab initio calculations. Based on the information gathered in this study, a critical re-assessment of the Pu-Zr system involving the f (Pu 28 Zr), h (Pu 4 Zr), kinetically hindered j (PuZr 2 ), and once observed i phases is called for.This article is an invited paper selected from presentations at ''PSDK XIV: Phase Stability and Diffusion Kinetics-Gibbs: Phase Equilibria, Diffusion and Materials Design'' held during MS&T'19, September 29-October 3, 2019, in Portland, Oregon. The special sessions were dedicated to honor Dr. Patrice Turchi, recipient of the ASM International 2019 J. Willard Gibbs Phase Equilibria Award ''for outstanding and pioneering contributions in the application of first-principles, quantum-mechanical calculations to the modeling of phase equilibria and thermodynamic behavior of alloys.'' It has been expanded from its original presentation.

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“…Therefore, the use of DFT-derived properties associated with the CALPHAD assessment constrains the optimization and validates the final thermodynamical database, not only from a phase-diagram standpoint, but also from an energetics standpoint. In the literature, one readily finds first-principles-informed CALPHAD assessments for actinides [30][31][32].…”

Section: Calphad Methodsmentioning

confidence: 99%

Thermodynamics of Uranium Tri-Iodide from Density-Functional Theory

et al. 2020

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Density-functional theory (DFT) is employed to investigate the thermodynamic and ground-state properties of bulk uranium tri-iodide, UI3. The theory is fully relativistic and electron correlations, beyond the DFT and generalized gradient approximation, are addressed with orbital polarization. The electronic structure indicates anti-ferromagnetism, in agreement with neutron diffraction, with band gaps and a non-metallic system. Furthermore, the formation energy, atomic volume, crystal structure, and heat capacity are calculated in reasonable agreement with experiments, whereas for the elastic constants experimental data are unavailable for comparison. The thermodynamical properties are modeled within a quasi-harmonic approximation and the heat capacity and Gibbs free energy as functions of temperature agree with available calculation of phase diagram (CALPHAD) thermodynamic assessment of the experimental data.

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The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study

Cited by 17 publications

References 36 publications

Ground-State and Thermodynamical Properties of Uranium Mononitride from Anharmonic First-Principles Theory

Ground-State and Thermodynamical Properties of Uranium Mononitride from Anharmonic First-Principles Theory

Experimental and Modeling Review of the Plutonium-Zirconium (Pu-Zr) System: Lost in Translation and Over Time?

Thermodynamics of Uranium Tri-Iodide from Density-Functional Theory

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