Research on mechanical and high temperature properties of C/SiC ceramic matrix composites

2017-06-01

【Author】 Yin Xiaoguang;

【Instructor】Miao Wei;

[Basic information about the author] Tsinghua University, Materials Science and Engineering, 2011, Master

【Abstract】 SiC ceramic has the characteristics of high strength, low density, excellent thermal shock resistance and oxidation resistance. However, its shortcoming is high brittleness, which seriously limits its application as a structural material. Carbon fiber has good high-temperature mechanical and thermal properties, and has good physical and chemical compatibility with silicon carbide. Therefore, since the 1970s, carbon fiber reinforced silicon carbide ceramic matrix composites (C/SiCCMCs) have become a new hot spot in the field of structural materials research. The C/SiC composite material is reinforced and toughened by continuous carbon fibers. On the one hand, it improves the toughness of the composite material. On the other hand, it retains the advantages of high strength and high temperature resistance of the SiC ceramic matrix. It is a new type of high-temperature structural material and functional material. It has been increasingly widely used in important military and civilian fields, such as high-temperature components of aerospace engines, rocket nozzles, space shuttle thermal protection systems, and nuclear reactor first wall materials. Therefore, the study of the mechanical properties and high-temperature properties of C/SiC composite materials is of great significance. This paper prepared three different C/SiC composite materials: 3D braided, 2.5D braided and 2D needle punched C/SiC composite materials, and studied their bending properties, thermal expansion properties and high-temperature ablation properties from the perspective of microstructure. The mechanism was discussed, and the effects of different preparation processes on the material microstructure and the above properties were analyzed through comparisons between different composite materials. The results of the study on the bending properties of C/SiC composites show that the 2.5D braided C/SiC composites prepared in this article have... more reduction

【Key words】 C/SiC; composite materials; bending strength; thermal expansion coefficient; ablation;