Remarkable long-term oxidation resistance of high-entropy alumino-silicides up to 2100 °C

Thermal protection systems of hypersonic vehicles typically require advanced high-temperature materials capable of withstanding long-term exposure to oxidizing environments at 1800–2500 °C. 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 °C 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 °C. 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 cm 2 ⋅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.