真空吸浆法制备C/SiC复合材料及力学性能研究

Preparation and Mechanical Property of C/SiC Composite by Vacuum Infusion Method

以碳毡为预制体,将SiC粉末、酚醛树脂等搅拌成混合浆液,采用真空吸浆法制备C/SiC复合材料,测定其密度、孔隙率和力学强度,利用扫描电镜(SEM)研究其断裂面的微观结构并分析失效机制。结果表明:真空吸浆两次后C/SiC复合材料的致密性、力学强度随着浆料中SiC含量的增加均呈先增加后减小的变化趋势,其裂纹扩展过程包括纤维/基体脱粘、纤维桥连、纤维摩阻、裂纹偏转、纤维拔出等几种增韧增强机制。综合比较,当浆料中SiC含量为25%(质量分数)时,其致密性和力学性能最好,密度为1.31g/cm3,孔隙率为15.10%,抗弯强度和抗压强度分别达84.04MPa和74.22MPa,材料具有较好的韧性。

C/SiC composite was fabricated by vacuum infusion method to infiltrate mixing slurry of the SiC powder,phenolic resin and etcinto carbon felt.The density,porosity and the mechanical strength of C/SiC composite were determined.The microstructure of C/SiC composite was studied by scanning electron microscope（SEM）,meanwhile failure mechanism of C/SiC composite were analyzed.The results show that the compactness and mechanical property of C/SiC composite fabricated by two times vacuum infusion method twice exhibit the changing trend of going up first and falling down later as SiC content increasing in the slurry,the crack propagation process includes several toughening enhancement mechanisms：fiber/matrix debonding,fiber-bridging,fiber friction,crack deflection,fiber pull-out.After comprehensive comparation,when content of SiC is 25%（mass fraction）,the compactness and mechanical properties of the C/SiC composite are optimum.Its density reaches 1.31g/cm3,porosity is 15.10%,bending strength and compressive strength are 84.04 MPa and 74.22 MPa respectively,C/SiC composite has good toughness.