不同SiC源对Cf/ZrB2–SiC复合材料微结构和力学性能的影响  

Effect of SiC Source on Microstructures and Mechanical Properties of Cf/ZrB2–SiC Composites

作　　者：张幸红[1] 张东洋 胡平[1] 方成 ZHANG Xinghong;ZHANG Dongyang;HU Ping;FANG Cheng(Center for Composite Materials and Structures,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]哈尔滨工业大学复合材料与结构研究所

出　　处：《硅酸盐学报》2018年第12期1694-1699,共6页Journal of The Chinese Ceramic Society

基　　金：国家杰出青年基金(51525201)资助

摘　　要：采用新型浆料注射/真空浸渍工艺实现了超高温陶瓷组分与碳纤维的有效复合,并结合低温(1 450℃)热压烧结实现了Cf/ZrB2-SiC复合材料的制备。研究了不同SiC源(SiC粉体和聚碳硅烷PCS)对复合材料微结构和力学性能的影响,结果表明:基于聚碳硅烷优异的流动性实现了陶瓷组分在纤维束内和束间的有效填充,并经低温热压烧结后Cf/ZrB2-PCS复合材料的相对密度为91.3%,主要归结于聚碳硅烷裂解后残留的微量无定性碳起到了表面除氧的作用而促进致密化,但该无定性碳弱化了晶界强度而导致力学性能降低。同时Cf/ZrB2-PCS复合材料表现出非脆性断裂模式且断裂功高达539 J/m^2,较Cf/ZrB2-SiCp复合材料提升高达84.6%;该复合材料断裂功的提升主要归结于裂纹偏转、裂纹分叉和纤维桥联等多种增韧机制的协同效应,大幅度改善了ZrB2基超高温陶瓷材料的损伤容限和可靠性。The Cf/ZrB2-SiC composite with uniform architecture was fabricated by a low-temperature(i.e., 1 450 ℃) hot pressing technique. The effect of SiC resource(i.e., SiC powder and polycarbosilane) on the microstructures and mechanical properties of Cf/ZrB2-SiC composites was investigated. The results showed that the ceramic component could be effectively introduced into the intrafascicular and interfascicular spaces of carbon fiber bundles due to the excellent fluidity of liquid PCS. In addition, the relative density of the Cf/ZrB2-PCS composite was 91.3%, which was attributed to the surface oxygen removal by the residual amorphous carbon to promote the densification. However, the existence of amorphous carbon weakened the grain boundary strength, resulting in the decrease of flexural strength. The Cf/ZrB2-PCS composite exhibited a non-brittle fracture mode with a work of fracture of 539 J/m^2, which was up to 84.6% compared with Cf/ZrB2-SiCp composite. The enhancement of work of fracture was attributed to the hybrid toughening mechanisms such as crack deflection, crack branching and fiber bridging, which greatly improved the damage tolerance and reliability of ZrB2-based ultra-high temperature ceramics.

关 键 词：陶瓷基复合材料 碳化硅粉体 聚碳硅烷 浆料注射 热压烧结 断裂功 

分 类 号：TB302[一般工业技术—材料科学与工程]