固体冲压发动机燃气阀用C/SiC复合材料研究

Study on the C/SiC composites for hot gas valve of solid propellant ramjet

采用“化学气相渗透法+先驱体浸渍裂解法”(CVI+PIP)混合工艺制备了固体冲压发动机燃气阀用3D C/S iC复合材料,并对复合材料的显微结构和力学性能进行了研究。复合材料的密度为2.1 g/cm3,复合材料的室温剪切强度和轴向弯曲强度分别为55 MPa和643 MPa。在断裂过程中,复合材料表现出明显非灾难性的韧性断裂行为,试样断裂面存在大量的拔出纤维。复合材料具有优异的绝热性能,Z向热导率为14.5 W/(m.K),X-Y面内热导率为5.0 W/(m.K)。研制的3D C/S iC复合材料燃气阀成功通过冷气轴向抗冲击试验和发动机高温搭载试验考核。

Carbon fiber reinforced silicon carbide matrix composites （3D C/SiC） for hot gas valve of solid propellant ramjet were prepared by using＂chemical vapor infiltration ＋ precursor impregnation pyrolysis＂（ CVI ＋ PIP） hybrid process. The mechanical properties and microstructure of 3D C/SiC composites were investigated. The density of 3D C/SiC composites can reach 2.1 g/cm^3 ,and the shear strength and axial flexural strength are 55 MPa and 643 MPa respectively at room temperature. In the course of fracture, the composites present obvious nondestructive toughness fracture behaviour with many pulled-out fibers in the fracture cross-section. The composites possess superior insulation property with thermal conductivity of 14.5 W/（ m · K） at Z-direction and 5.0 W/（ m · K） at X-Y plane. The 3D C/SiC hot gas valves of solid propellant ramjet successfully pass the cool gas axial impact test and high-temperature gas test.