碳纤维预制体结构对CVI-GSI C/C-SiC复合材料微观结构与力学性能的影响  

Influence of carbon fiber preform structure on microstructure and mechanical properties of C/C-SiC composites fabricated by combined CVI-GSI method

作　　者：缪花明 刘荣军[1] 王衍飞[1] 李俊生[1] 李端 万帆[1] MIAO Huaming;LIU Rongjun;WANG Yanfei;LI Junsheng;LI Duan;WAN Fan(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory,College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学空天科学学院新型陶瓷纤维及其复合材料重点实验室,长沙410073

出　　处：《材料工程》2023年第8期142-148,共7页Journal of Materials Engineering

基　　金：国家重点研发计划项目(2021YFB3701500)。

摘　　要：采用不同面密度和丝束大小的碳纤维布,通过不同z向缝合方式编织了两种碳布叠层结构的碳纤维预制体,再经化学气相渗透法(chemical vapor infiltration,CVI)与气相渗硅法(gaseous silicon infiltration,GSI)联用制备了C/C-SiC复合材料。研究了碳纤维预制体结构对CVI-GSI C/C-SiC复合材料微观结构与力学性能的影响。结果表明,由纤维体积分数与C/C素坯密度都相同的预制体所制备的两种复合材料的密度、各相组成、结构与性能均大不相同。较小的碳纤维丝束(1K)和碳布面密度(92 g/m^(2)),以及锁式缝合留下的较大孔隙为GSI反应中Si蒸气的渗透提供了更加充足的通道,最终制备的T1复合材料孔隙率低、结构均匀、性能更高,其弯曲强度、模量和断裂韧度分别为300.97 MPa,51.75 GPa,11.32 MPa·m^(1/2)。初始预制体结构和C/C中间体结构的综合调控是CVI-GSI联用工艺制备高性能C/C-SiC复合材料的关键。Using carbon fiber cloth with different areal densities and tow sizes,two kinds of carbon fiber preforms with same carbon cloth laminated structure were produced through different z-direction stitching methods.Then,C/C-SiC composites were prepared by combining chemical vapor infiltration(CVI)with gas silicon infiltration(GSI).The influence of carbon fiber preform structure on the microstructure and mechanical properties of CVI-GSI C/C-SiC composites was studied.The results show that the density,phase composition,structure,and properties of the two composites prepared from preforms with the same fiber volume fraction and C/C preform density are significantly different.The smaller carbon fiber tow(1K)and carbon cloth surface density(92 g/m^(2)),as well as the larger voids left by lock stitching,provide more sufficient channels for the infiltration of Si vapor in the GSI reaction process.Thus T1 composite finally prepared has low porosity,uniform structure,and higher performance,with bending strength,modulus,and fracture toughness of 300.97 MPa,51.75 GPa,and 11.32 MPa·m^(1/2),respectively.The comprehensive control of the initial preform structure and the C/C intermediate structure is the key to the preparation of high performance C/C-SiC composites by the CVI-GSI process.

关 键 词：C/C-SIC复合材料 预制体结构 气相渗硅 化学气相渗透 碳布叠层 

分 类 号：TB332[一般工业技术—材料科学与工程]