Thermodynamic-Guided Transport Properties of Liquid Pb-Bi Alloys via Molecular Interaction Modeling

Abstract

Liquid Pb-Bi alloys are pivotal for next-generation nuclear and solar energy systems, yet predicting their thermodynamic and transport properties remains challenging due to complex atomic interactions. This study integrates electromotive force measurements with the molecular interaction volume model (MIVM) to accurately calculate Pb-Bi thermodynamic properties (activity coefficients, Gibbs free energy, and mixing entropy) while establishing direct links to surface tension and viscosity. We demonstrate that MIVM achieves high precision and, combined with Gąsior’s entropy model, successfully predicts viscosity across broad temperature and composition ranges. Surface tension predictions demonstrate excellent agreement with experimental measurements, highlighting the preferential segregation of Bi atoms at the interface and temperature-induced structural homogenization across varying compositions. The unified framework resolves discrepancies in prior models by leveraging excess entropy and molecular interactions, offering critical insights for optimizing liquid metal coolants in advanced reactor and energy systems.