Molecular dynamics simulation on the dissolution and diffusion characteristics of FeCrAl alloy in liquid LBE

Abstract

Lead-bismuth eutectic (LBE) corrosion-resistant materials are crucial for the development of future fourth-generation nuclear reactors, and the dissolution and diffusion of material components are important processes in LBE corrosion-resistant materials. FeCrAl alloy is an important structural material for fourth-generation reactors, and it is essential to study its dissolution and diffusion processes in liquid LBE. Molecular dynamics simulations (MD) were used to investigate the mutual diffusion process between the FeCrAl alloy and liquid LBE. The dissolution and diffusion abilities of Fe, Cr, and Al atoms in liquid LBE were evaluated using mean-square displacement (MSD) and diffusion activation energy (DAE). Fe atoms exhibited the highest degree of diffusion, while Al atoms showed the lowest degree of diffusion, resulting in a distinct difference in the elemental distribution at the solid–liquid interface (SLI). There was a significant difference in the depth of penetration of Pb and Bi atoms into the FeCrAl alloy matrix, with Bi atoms penetrating deeper. Furthermore, there is a thermal vibration process during the invasion of Pb and Bi atoms into the FeCrAl alloy matrix, which promotes the invasion process of Pb and Bi atoms. In addition, an increase in temperature exacerbates the diffusion of Fe, Cr, and Al atoms in liquid LBE and the process of Pb and Bi atom invasion into the FeCrAl alloy matrix. Our research may contribute to the design of future nuclear-grade FeCrAl alloy and the development of next-generation reactors.