CHEN Shugang 1 MA Qingsong 1 LIU Weidong 2 LIU Haitao 1,2
(1.National Key Laboratory of Science and Technology on Advanced Ceramic Fibers & Composites, National University of Defense Technology, Changsha Hunan 410073, China; 2.Science and Technology on Scramjet Laboratory, National
University of Defense Technology,Changsha Hunan 410073, China)
Abstract: Mullite (3A12O3·2SiO2) has the characteristics of high resistance to creep, corrosion and thermal shock, and has a low thermal expansion coefficient and a low thermal conductivity, which make it a structural material with good potential foreground. The most outstanding advantage of mullite is that its flexural strength and fracture toughness rise with the temperature. However, it has relatively poor mechanical properties at room temperature, which limits its applications. In order to improve the flexural strength and fracture toughness at room temperature, many researches have been conducted, which focus on the method of adding the secondary phase and make some progress. This article introduces the current condition of mechanical properties improvement by discontinuous phase (particles, whiskers and short fibers) and continuous fibers, including the fabrication, microstructures and main properties, and points out the exiting problems and the tendency in the future.
Key words: mullite; composites; the secondary phase; toughening mechanism; mechanical properties