CVD-SiC界面改性涂层对气相渗硅制备C_f/SiC复合材料力学性能的影响  

Effect of CVD-SiC Interface Modification Coating on the Mechanical Properties of C_f/SiC Composite Prepared by Gaseous Silicon Infiltration Process

作　　者：刘荣军[1] 曹英斌[1] 杨会永[1] 严春雷[1] 龙宪海[1] LIU Rong-jun;CAO Ying-bin;YANG Hui-yong;YAN Chun-lei;LONG Xian-hai(Key Laboratory of Advanced Ceramic Fibers and Composites, School of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073 , China)

机构地区：[1]国防科学技术大学航天科学与工程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》2018年第1期37-43,共7页Journal of Materials Engineering

基　　金：国家自然科学基金(51102282);国防科学技术大学科研计划项目(JC14-01-01)

摘　　要：在气相渗硅制备C_f/SiC复合材料时,界面改性涂层非常重要。良好的界面改性涂层一方面起到保护碳纤维不受Si反应侵蚀的作用,另一方面起到调节纤维和基体界面结合状况。通过在C纤维表面制备CVD-SiC涂层来进行界面改性,研究CVD-SiC界面改性涂层对GSI C_f/SiC复合材料力学性能和断裂特征的影响,并分析其影响机制。结果表明:无CVD-SiC涂层改性的C_f/SiC复合材料力学性能较差,呈现脆性断裂特征,其强度、模量和断裂韧度分别为87.6MPa,56.9GPa,2.1MPa·m1/2。随着CVD-SiC涂层厚度的增加,C_f/SiC复合材料的弯曲强度、模量和断裂韧度呈现先升高后降低的趋势,CVD-SiC涂层厚度为1.1μm的C_f/SiC复合材料的力学性能最好,其弯曲强度、模量和断裂韧度分别为231.7MPa,87.3GPa,7.3MPa·m1/2。厚度适中的CVD-SiC界面改性涂层的作用机理主要体现在载荷传递、"阻挡"Si的侵蚀、"调节"界面结合状态3个方面。The interface plays a key role on the mechanical properties of Cr/SiC composite prepared by GSI process. The ideal interface should not only prevent carbon fiber from being etched by Si vapor, but also adjust the bonding force between C fiber and SiC matrix. SiC coating prepared by CVD was chosen as the interface and its effect on the mechanical properties and fracture features of GSI Cr/SiC composite was discussed, and the influencing mechanism was analyzed. The results show that GSI Cr/ SiC composite without CVD-SiC interface has poor mechanical properties, exhibiting brittle fracture feature. The bending strength, elastic module and fracture toughness are 87. 6MPa, 56. 9GPa and 2. IMPa ？ m1/2, respectively. The mechanical properties of GSI Cr/SiC increase with the increase of the thickness of CVD-SiC coating at first, then decrease with the continuous increase of the thickness of CVD-SiC coating. The Cr/SiC composite with 1. l^m thickness of CVD-SiC coating has the best mechanical properties, and the bending strength, elastic module and fracture toughness are 231. 7MPa, 87. 3GPa and 7. 3MPa· m1/2 , respectively. The action mechanism of CVD-SiC interface coat-ing on the composite is mainly on the three aspects： load transfer, preventing C fiber from being etched by Si and adjusting fiber/matrix bonding status.

关 键 词：CVD SIC 界面改性涂层 气相渗硅 CF/SIC复合材料 力学性能 

分 类 号：TB332[一般工业技术—材料科学与工程]