C/C多孔体的高温热处理对C/SiC复合材料结构及力学性能的影响

The Effects of Heat Treatment of C/C Porous Substance on Microstructure and Mechanical Property of C/SiC Composites

以三维针刺碳毡作为预制体,先采用树脂单向加压浸渍-热解工艺制备出C/C多孔体,再通过反应熔体浸渗法获得C/SiC复合材料。重点研究了C/C多孔体的高温热处理对C/SiC复合材料结构和力学性能的影响。结果表明,C/C多孔体的高温热处理不会改变C/SiC复合材料的相组成,但可使复合材料中的SiC含量提高,C含量降低;高温热处理有利于熔融Si浸渗,使复合材料致密度增大,孔隙率降低,从而使其弯曲断裂强度提高约28%;高温热处理还可使纤维-基体界面结合强度降低,改善复合材料的断裂韧性。

Carbon/carbon （C/C） porous substance was mensional needle-punched carbon fiber preform. C/C porous prepared via resin impregnation-pyrolysis from three disubstance was transformed into carbon/silicon carbide （C/SiC） composites by liquid silicon infiltration. Effects of heat treatment （HTT） of C/C porous substance on micro-structure and mechanical property of C/SiC composites were investigated. The results indicate that the phase composition of C/SiC composites does not change after C/C HTT, but an increase and a decrease in SiC and C contents are observed, respectively. C/C HTT is beneficial for the Si infiltration, thus the fabricated C/SiC composites have higher density and lower porosity which cause the bending fracture strength of C/SiC composites increases about 28%. Fiber/matrix interface binding strength is reduced by HTT and a much better fracture toughness is also obtained.