Microstructure and properties of a multilayered laser cladding Al0.2NbTiV0.1W0.5Zr0.3 high-entropy alloy coating on a zirconium alloy

The corrosion and wear requirements of Zr alloys for application as fuel cladding materials are becoming increasingly stringent. Accordingly, developing surface engineering techniques and high-performance coating materials is crucial for achieving improved surface properties of these alloys. Herein, we propose a strategy for preparing high-performance coatings on Zr alloys using the multilayer cladding technique to prevent the high dilution of Zr alloy substrates because of high-energy beams. A novel Al0.2NbTiV0.1W0.5Zr0.3 high-entropy alloy (HEA) coating with a multilayer structure was prepared on a Zr alloy using multiple laser claddings. The top-layer and interlayer were composed of two body-centered cubic (BCC) phases and a Zr-rich phase. Owing to the multilayer cladding, the top-layer was almost unaffected by matrix dilution and substrate evaporation, leading to a significantly reduced precipitation of the Zr-rich phase in the top-layer. The high hardness and excellent wear resistance of the coating were attributed to the two BCC phases; moreover, both, the Zr-containing HEA and substrate, exhibited adhesive wear. The top-layer exhibited superior pitting corrosion properties, whereas the microstructural inhomogeneity in the interlayer led to intergranular corrosion, dominating the corrosion process. Thus, this study presents a coating material system suitable for Zr alloys with excellent wear and corrosion resistances. The findings can potentially contribute to expanding the application of the high-energy beam technology to Zr alloys. [Display omitted] •Al0.2NbTiV0.1W0.5Zr0.3 HEA coating with multilayer structure was prepared on Zr alloy by multiple laser cladding.•The microstructure and properties of top-layer and interlayer on the multi-layer strategy were investigated.•The Zr-rich phase and two coexisting BCC phases are formed in the coating.•IGC dominates the corrosion process in the interlayer owing to microstructural inhomogeneity.•The corrosion and wear resistance of Zr alloy surface are significantly improved.