Revisiting thermodynamics and kinetic diffusivities of uranium-niobium with Bayesian uncertainty analysis Academic Article uri icon


  • 2016 In this work, thermodynamic and kinetic diffusivities of uraniumniobium (UNb) 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 -UNb 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 2/+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 -UNb. Finally, Bayesian analysis is conducted to evaluate the uncertainty of the thermodynamic model and its impact on the system's phase stability.

published proceedings


author list (cited authors)

  • Duong, T. C., Hackenberg, R. E., Landa, A., Honarmandi, P., Talapatra, A., Volz, H. M., ... Arroyave, R.

citation count

  • 46

complete list of authors

  • Duong, Thien C||Hackenberg, Robert E||Landa, Alex||Honarmandi, Pejman||Talapatra, Anjana||Volz, Heather M||Llobet, Anna||Smith, Alice I||King, Graham||Bajaj, Saurabh||Ruban, Andrei||Vitos, Levente||Turchi, Patrice EA||Arroyave, Raymundo

publication date

  • January 2016