High-Temperature Corrosion Behavior of High-Entropy Alloys in Liquid Ce

Abstract

During the smelting of uranium (U) and its alloys, molten U readily reacts with crucible and mold materials at elevated temperatures, causing contamination of the smelting system and raw materials. With exceptional high-temperature structural stability and molten corrosion resistance, refractory high-entropy alloys are regarded as promising candidate crucible materials for U alloy smelting. In this work, NbTaTiW, NbTaTiAl, and NbTaTiAlW alloys were prepared via arc melting, and their as-cast microstructures as well as corrosion performance in molten cerium (Ce, a non-radioactive simulant for U) at 1400 °C were systematically investigated. The results reveal that all three as-cast alloys possess a single-phase body-centered cubic structure with typical dendritic morphology. The NbTaTiW alloy exhibits the optimal molten Ce corrosion resistance, with an average corrosion rate of 0.42 μm/h after 50 h of immersion. The alloys exhibit pronounced susceptibility to intergranular corrosion. Furthermore, the addition of Al, or the substitution of W with Al, markedly promotes mutual dissolution and interfacial diffusion between molten Ce and the alloy matrix, thereby accelerating the initiation and propagation of intergranular corrosion. This study provides a new design strategy for developing high-temperature contact materials with superior resistance to molten uranium corrosion.