Thermal protection systems of hypersonic vehicles typically require advanced high-temperature materials capable of withstanding long-term exposure to oxidizing environments at 1800–2500 ℃. However, related studies are scarce. Here, by employing a laser-assisted compositional engineering strategy, we successfully explore innovative high-entropy alumino-silicides (HEASs) that show superior long-term oxidation resistance across 1700–2100 ℃ for 80 min in air, surpassing the performance of previously reported ultrahigh-temperature materials. The oxidation resistance of HEASs is further validated by plasma ablation testing in air, exhibiting a linear ablation rate of as low as 0.035 μm·s⁻¹ at 2100 ℃. Such remarkable oxidation resistance is attributed to the formation of a unique alumino-silicate glassy phase. Further first-principles calculations coupled with experimental observations indicate an ultralow oxygen diffusion rate (4.26 × 10⁻⁵ cm²·s⁻¹) and exceptional thermal stability (binding energy of −0.004 eV·Å⁻²) in the alumino-silicate glassy phase due to multi-component synergistic effects. This work highlights the potential of HEASs for long-term ultrahigh-temperature applications.

Exploring superior calcium-magnesium-aluminosilicate (CMAS) corrosion resistance is crucial for high-entropy rare-earth monosilicates (HEREMs) as the next-generation environmental barrier coating (EBC) materials. However, related studies are rarely reported. This work presents the exploration of HEREMs with remarkable CMAS corrosion resistance by engineering their compositions. The equimolar 3-to-9 cation high-entropy rare-earth monosilicate (3-9HEREM) specimens were initially prepared using a pressure-less sintering technique; subsequently, their resistance to CMAS corrosion was evaluated at temperatures up to 1600 ℃. The results demonstrate that the 5HEREM specimens possess the best CMAS corrosion resistance among all the as-fabricated specimens, surpassing other reported EBC materials. Such remarkable CMAS corrosion resistance results from the generation of a dense apatite protective layer originating from its low dissolution rate at elevated temperatures.