C/C多孔体对C/C-SiC复合材料微观结构和弯曲性能的影响  

EFFECT OF C/C POROUS PREFORM ON THE MICROSTRUCTURE AND FLEXURAL STRENGTH OF C/C-SiC COMPOSITES

作　　者：张永辉[1] 肖志超[1,2] 王继平[1] 乔冠军[1] 金志浩[1] 

机构地区：[1]西安交通大学,金属材料强度国家重点实验室,西安710049 [2]西安航天复合材料研究所超码科技有限公司,西安710025

出　　处：《硅酸盐学报》2008年第8期1069-1073,共5页Journal of The Chinese Ceramic Society

摘　　要：以4种纤维含量相同(32%,体积分数,下同),用化学气相渗透(chemical vapor infiltration,CVI)法制备了4种密度的碳纤维增强碳(carbon fiber reinforced carbon,C/C)多孔体,基体炭含量约20%～50%。利用液相渗硅法(liquid silicon infiltration,LSI)制备了C/C–SiC复合材料,研究了C/C多孔体对所制备的C/C–SiC复合材料微观结构和弯曲性能的影响。结果表明:不同密度的C/C多孔体反应渗硅后,复合材料的物相组成均为SiC,C及单质Si;随着C/C多孔体中基体炭含量的增加,C/C–SiC复合材料中SiC含量逐渐减少而热解炭含量逐渐增加。C/C–SiC复合材料弯曲强度随着材料中残留热解炭含量增加而逐渐增加,热解炭含量为约42%的C/C多孔体所制备的C/C–SiC复合材料的弯曲强度最大,达到320MPa。Carbon fiber reinforced silicon carbide matrix （C/C-SiC） composites were prepared by liquid silicon infiltration （LSI） process, using four kinds of quasi-three dimensional C/C preforms with the same fiber volume faction （32%） but different pyrocarbon content （from -20% to -50%, in volume） filled by chemical vapor infiltration. The microstructure and flexural strength of C/C-SiC composites have been investigated. XRD analysis results show the composites are composed of three phases ofβ-SiC, C and Si. With the increase of the pyrocarbon content in the C/C preforms, the content of formed silicon carbide in the C/C-SiC composites decreases but the residual pyrocarbon increases. Flexural test was performed to assess the role of the matrix in the C/C-SiC composites. The results demonstrate that the flexural strength of the composite increases gradually as the increase of the content of residual pyrocarbon. The bending strength of the C/C-SiC composite produced of the C/C preform with pyrocarbon content of -42% is the highest of 320 MPa.

关 键 词：陶瓷基复合材利 基体炭 显微结构 弯曲性能 液相渗硅法 化学气相渗透 

分 类 号：TB332[一般工业技术—材料科学与工程]