Microstructure and mechanical properties of Al matrix composites produced by Al-CeO2 in-situ reaction

This study reports a breakthrough in designing heat-resistant Al matrix composites through a controlled Al-CeO₂ in-situ reaction, achieving exceptional thermal stability via a novel interfacial mutual stabilization mechanism between amorphous Al₂O₃ (am-Al₂O₃) and Al₁₁Ce₃. By regulating the hot-pressing temperature (490–610 °C), it is demonstrated that the tensile strength can be modulated over a 52 % range (143–218 MPa, 350 °C), directly governed by the evolution of a unique core-shell structure where am-Al₂O₃ layers encapsulate Al₁₁Ce₃ and CeO₂ nanoparticles. Detailed characterization reveals that the am-Al₂O₃ shell effectively suppresses Al₁₁Ce₃ coarsening, while the Al₁₁Ce₃ core chemically stabilizes the am-Al₂O₃ against crystallization – a reciprocal stabilization effect. The composite retains >98.8 % of its original strength after annealing at 350 °C for 1000 h and 450 °C for 360 h. Concurrently, the composite displays exceptional corrosion resistance (0.03 mg·cm⁻³ weight loss vs. 4.14 mg·cm⁻³ for 2219 Al alloy). This work establishes a new materials design paradigm leveraging amorphous-crystalline interfacial synergy, providing a pathway to tailor high-temperature composites.