AbstractAlCrMoNbZr high-entropy alloys (HEAs) with varying zirconium (Zr) compositions were used for nuclear fuel cladding. The alloys were fabricated using the arc melting method. This study investigates the effect of varying Zr compositions in AlCrMoNbZr HEAs on their microstructure, mechanical properties, and corrosion resistance. AlCrMoNbZr HEAs with Zr atomic percentages of 5%, 10%, 15%, 20%, and 25% were characterized using X-ray diffraction (XRD), Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS), Vickers hardness testing, and corrosion tests in LiOH + H3BO3 and 3% NaCl solutions. The characterization results showed that increasing the Zr content led to a structural transition from the dominance of Cr2Zr and Mo phases at lower concentrations to the formation of Al2Zr phases at higher concentrations. The alloy morphology also changed from a dendritic to an equiaxial structure with increasing Zr content. This structural evolution contributed to increased material hardness, reaching a maximum value of 829.28 HV in the alloy with 25% Zr. However, corrosion tests indicated that the alloy's lowest corrosion rate was achieved with 5% Zr, with rates of 0.00048 mmpy in LiOH + H3BO3 and 0.00028 mmpy in 3% NaCl solution. Contact angle evaluations revealed that alloys with higher Zr contents exhibited greater hydrophilic properties. This study demonstrates that optimizing the Zr content in AlCrMoNbZr HEAs can significantly enhance their performance as promising candidates for nuclear fuel cladding materials capable of withstanding extreme conditions. © 2026 Korean Nuclear Society, Published by Elsevier Korea LLC. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/