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Title: Revisiting thermodynamics and kinetic diffusivities of uranium–niobium with Bayesian uncertainty analysis

Journal Article · · Calphad
 [1];  [2];  [3];  [1];  [1];  [2];  [2];  [2];  [2];  [4];  [5];  [5];  [3];  [1]
  1. Texas A & M Univ., College Station, TX (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. Royal Institute of Technology, Stockholm (Sweden)
+ Show Author Affiliations

In this work, thermodynamic and kinetic diffusivities of uranium–niobium (U–Nb) are re-assessed by means of the CALPHAD (CALculation of PHAse Diagram) methodology. In order to improve the consistency and reliability of the assessments, first-principles calculations are coupled with CALPHAD. In particular, heats of formation of γ-U–Nb are estimated and verified using various density-functional theory (DFT) approaches. These thermochemistry data are then used as constraints to guide the thermodynamic optimization process in such a way that the mutual-consistency between first-principles calculations and CALPHAD assessment is satisfactory. In addition, long-term aging experiments are conducted in order to generate new phase equilibria data at the γ 2 /α+γ 2 boundary. These data are meant to verify the thermodynamic model. Assessment results are generally in good agreement with experiments and previous calculations, without showing the artifacts that were observed in previous modeling. The mutual-consistent thermodynamic description is then used to evaluate atomic mobility and diffusivity of γ-U–Nb. Finally, Bayesian analysis is conducted to evaluate the uncertainty of the thermodynamic model and its impact on the system's phase stability.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
Grant/Contract Number:
AC52-07NA27344; AC52-06NA25396; DMR-1410983; CMMI-1534534; AC02-05CH11231
OSTI ID:
1368005
Alternate ID(s):
OSTI ID: 1334151; OSTI ID: 1411073; OSTI ID: 1440946
Report Number(s):
LLNL-JRNL-703367; LA-UR-16-22697
Journal Information:
Calphad, Vol. 55, Issue P2; ISSN 0364-5916
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 42 works
Citation information provided by
Web of Science

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Cited By (2)

Uncertainty Quantification and Propagation in Computational Materials Science and Simulation-Assisted Materials Design journal January 2020
Sensitivity estimation for calculated phase equilibria text January 2020

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75 CONDENSED MATTER PHYSICS
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71 CLASSICAL AND QUANTUM MECHANICS
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36 MATERIALS SCIENCE
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