Thermodynamic and diffusion databases for uranium-based alloys and their applications in materials design

Thermodynamic and diffusion databases are of fundamental importance for material design. In this work, the thermodynamic and diffusion databases for multicomponent U alloys are developed using the CALPHAD (CALculation of PHAse Diagram) method. Thermodynamic models are employed to de-scribe all phases in the U -Nb -Zr -Ti -Mo -C system in which 7 ternary systems (U -Nb -Zr, U -Zr -Ti, U -Mo -Zr, Mo -Nb -Zr, Mo -Ti -Zr, C -Nb -Zr, and C -Nb -Ti) are thermodynamically assessed. Thermody-namic descriptions of all sub-systems from both literature and present assessments are integrated into the database with a proper adjustment. The diffusion database is developed for bcc and liquid phases in the U -Nb -Zr -Ti -Mo -C system. Applications of thermodynamic and diffusion databases are performed using two cases including (a) the stability of gamma U in the multicomponent system, and (b) discontinuous precipitation simulation in U-14 at.% Nb alloys. It is expected that further progress in CALPHAD-type nu-clear materials databases will be an effective contribution to advanced metal fuels design. (c) 2023 Published by Elsevier B.V.