低温反应熔渗制备C/C-SiC复合材料的微观结构和力学性能

Microstructure and Mechanical Properties of C/C-SiC Materials Fabricated by Low-Temperature Reactive Melt Infiltration

分别在1 450,1 500和1 550℃通过反应熔渗的方法制备了C/C-SiC复合材料,研究熔渗温度对C/C-SiC的性能影响。借助扫描电子显微镜,X射线衍射仪等对C/C复合材料及C/C-SiC复合材料的微观结构等进行表征,测试了C/C-SiC复合材料的弯曲性能。结果表明:熔渗温度不同影响C/C-SiC的密度、孔隙率、残余硅含量及弯曲强度。熔渗温度越高,C/C-SiC的密度越大,孔隙率越低,SiC含量越高,残余硅含量越少,弯曲强度越高。1 550℃反应熔渗制备的C/C-SiC1 550弯曲强度达到136MPa,比C/C-SiC1 450强度高出42%。C/C-SiC复合材料均表现出"假塑性"断裂行为,弯曲断裂过程中无纬布层中的碳纤维拔出明显。

C/C-SiC materials were fabricated by reactive melt infiltration(RMI)at three different temperatures of 1450,1500 and 1550℃to investigate the effects of the RMI temperature on the properties of C/C-SiC.Using scan electronic microscope,X-ray diffraction,etc.is to characterized the microstructures and phase compositions of C/C and C/C-SiC composites.The flexural strengths of C/CSiC composites were also tested.The results showed that:The higher RMI temperature was more likely to result in the higher density,lower porosity,more SiC,less residual Si and higher flexural strength of C/CSiC.The flexural strength of C/C-SiC1550 which was prepared at 1550℃ was 136MPa,42%higher than C/C-SiC1450’s.The fracture behavior of all C/C-SiC showed‘pseudo-plastic’manners,in which many carbon fibers of non-woven cloth pulling out were significantly demonstrated.