High temperature interaction of Y₄Al₂O₉/Y₂O₃ under CMAS exposure: Mechanism of outstanding corrosion resistance through composition design to accelerate reaction-induced CMAS consumption

The search for new materials with reliable molten calcium–magnesium–alumino–silicate (CMAS) resistance at elevated temperatures is important for the development of advanced aeroengines. In the present study, a novel Y₄Al₂O₉ (YAM)/Y₂O₃ composite was designed and fabricated from dense samples via the hot-pressing method. The interactions and mechanisms between the Y₄Al₂O₉/Y₂O₃ composite and CMAS at 1300 and 1500 °C for durations of 1, 4, 25, and 50 h were thoroughly explored. The results revealed that Y₄Al₂O₉/Y₂O₃ exhibited substantial resistance to CMAS infiltration at both temperatures, without notable grain-boundary penetration by CMAS glass. More importantly, the incorporation of reaction-active components in the composite accelerated the consumption of molten CMAS constituents and reduced their corrosive activity, which is recognized as the crucial principle for the composition design of anti-CMAS materials. This work provides valuable insights that can guide the design of the composition and advancement of superior CMAS-resistant materials.