(1. 中南大学 粉末冶金研究院，长沙 410083；
2. 航天材料及工艺研究所 先进功能复合材料技术重点实验室，北京 100076)
摘 要: 为了满足高超音速飞行器热结构部件材料的需求，采用化学气相沉积法(CVD)和反应熔渗法(RMI)混合工艺制备了叠层缝合C/C-SiC复合材料，研究C/C多孔体密度和熔渗温度对C/C-SiC复合材料微观结构和弯曲性能的影响。结果表明：C/C多孔体孔径呈双峰分布，孔体积随C/C多孔体密度增加而降低。C/C-SiC 复合材料由 SiC、C 及残余 Si 相组成。C/C-SiC复合材料弯曲强度随熔渗温度的升高而增加；1650 ℃制备的C/C-SiC复合材料弯曲强度随C/C多孔体密度升高先增加后略有减小，而1750 ℃制备C/C-SiC复合材料弯曲强度随C/C多孔体密度升高而升高。当C/C多孔体密度为1.55 g/cm3，熔渗温度为1750 ℃时，制备的C/C-SiC复合材料弯曲强度最高为253 MPa。在弯曲载荷作用下，C/C-SiC复合材料的位移-载荷曲线呈现“阶梯型”断裂行为。
关键字: C/C-SiC；叠层缝合结构；熔渗温度；C/C多孔体密度；弯曲强度
（1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
2. Science and Technology of Advanced Functional Composite Materials Laboratory, Aerospace Research Institute of Materials and Processing Technology, Beijing 100076, China）
Abstract:In order to meet the requirements of materials for hypersonic aircraft thermal structure components, the laminated suture structure C/C-SiC composites were prepared by mixed process of chemical vapor deposition (CVD) and reactive melt infiltration (RMI), the influence of C/C porous bodies density and infiltration temperature on the microstructure and flexural properties of C/C-SiC composites was investigated. The results show that the pore size of the C/C porous bodies has a bimodal distribution, and the pore volume decreases with the increase of the density of the porous bodies. C/C-SiC composites are composed of SiC, C and residual Si phases. The flexural strengths of C/C-SiC composites increase with the increase of infiltration temperature. The flexural strength of C/C-SiC composites prepared at 1650 ℃ firstly increases and then decreases slightly with the raise of C/C porous bodies density. At 1750 ℃, the flexural strength increases as the density of the C/C porous bodies increases. The maximum flexural strength of C/C-SiC composites is 253 MPa when the density of C/C porous is 1.55 g/cm3 and the infiltration temperature is 1750 ℃. Under the flexural loads, the displacement-load curves of C/C-SiC composites show a “stepped” fracture behavior.
Key words: C/C-SiC; laminated suture structure; infiltration temperature; C/C porous bodies density; flexural strength
