Microstructure, mechanical properties and thermal stability of Al2O3/Al2O3 ceramic matrix composites obtained from submicron-sized powers.

Improvement in thermal stability is especially important for the oxide/oxide composites, which are widely applied at high temperatures. Herein, the continuous alumina fiber reinforced alumina matrix (Al 2 O 3 /Al 2 O 3) composites were fabricated at 1200–1400 °C using Al 2 O 3 powders with a mean size of 0.6 μm. The Al 2 O 3 /Al 2 O 3 composite fabricated at 1300 °C achieved a high flexural strength of 392.9 ± 20.1 MPa and a high interlaminar shear strength of 20.6 ± 1.0 MPa. After exposure at 1000 °C for 100 h and 1400 °C for 10 min, the 1300 °C fabricated Al 2 O 3 /Al 2 O 3 composite showed no significant reduction in mechanical properties. A slight decrease in mechanical properties was observed after aging at 1200 °C for 100 h. The high strength retention after the heat treatment benefited from the coarse Al 2 O 3 powders, which could not be easily sintered at high temperatures. This work can expand the selection of the Al 2 O 3 /Al 2 O 3 composites for potential applications at service temperatures as high as 1400 °C for a short term. [ABSTRACT FROM AUTHOR]