SiC纳米线改善陶瓷基复合材料纤维/基体界面研究

Continuous fiber reinforced SiC matrix composites are promising candidate material for high temperature environments such as aerospace, gas turbine and thermo-nuclear fusion reactor. However,the mechanical properties of the SiC matrix composites, in particular, the fracture toughness, are still expected to be improved. In this research, the 1D nanomaterial, SiC nanowires are in situ grown on the fiber surface within the fiber fabric by chemical vapor deposition. Then the SiC matrix composites will be prepared by polymer infiltration and pyrolysis (PIP) technological route. Due to the huge surface/volume ratio and excellent mechanical properties of 1D nanomaterials, the in-situ growth of 1D nanomaterials on fiber surface is expected to enlarge the bond area between the fiber and matrix. The secondly pulled out of the 1D nanomaterials from the matrix consumes the deformation energies, resulting in the promotion of the mechanical properties for composites. Meanwhile, the effects of 1D nanomaterials growth and PIP process on the microstructure and properties of SiC matrix composites will be systematically investigated. This study is a fundamental research for the extending application of SiC matrix composite and is expected to develop a new technological route for ceramic composite reinforcement.

连续纤维增强SiC基复合材料是航空航天和核聚变等高技术领域理想的高温结构材料，然而其力学性能还有待进一步提高，特别是复合材料的断裂韧性，相比高温合金还有很大的差距。本研究以提高Si基复合材料的力学性能为目的，通过CVD和化学方法在纤维表面原位生长一维纳米材料SiC纳米线，并采用先驱体浸渍-裂解（PIP）工艺制备SiC纳米线改善界面的纤维增强SiC基复合材料。由于一维纳米材料具备巨大的比表面积和优异的力学性能，将SiC纳米线原位生长于复合材料纤维/基体界面，将大大增大纤维/基体之间结合界面的面积。在纤维拔出过程中，由于SiC纳米线的二次拔出而形成更多表面，吸收更多能量，增强复合材料断裂韧性。本研究系统研究一维纳米材料对纤维/基体界面结合强度的改善作用机理；探索纤维增强陶瓷基复合材料新的纳米增强途径和机理，为新的复合材料纳米增强体的设计和新的纤维增强陶瓷基复合材料体系设计提供科学依据。

连续纤维增强SiC基复合材料是航空航天和核聚变等高技术领域理想的高温结构材料，然而其力学性能还有待进一步提高。特别是复合材料的断裂韧性，相比高温合金还有很大的差距。本研究以提高Si基复合材料的力学性能为目的，采用化学方法对SiC纤维表面进行改性，然后加载催化剂，通过化学气相沉积（CVD）法在纤维表面原位生长一维纳米材料SiC纳米线，然后采用先驱体浸渍-裂解（PIP）方法制备SiC纳米线增强的SiCf/SiC复合材料。本项目系统研究了SiC纤维表面原位生长SiC纳米线的工艺与生长机理，系统研究了原位生长SiC纳米线对SiC纤维性能及复合材料纤维/基体结合强度的影响，探讨了SiC纳米线对SiCf/SiC复合材料增强机制。研究结果表明：原位生长SiC纳米线能有效提高SiCf/SiC复合材料力学性能，特别能有效提高SiCf/SiC复合材料断裂韧性40%以上。本项目研究探索了纤维增强陶瓷基复合材料新的纳米增强途径和机理，为新的复合材料纳米增强体的设计和新的纤维增强陶瓷基复合材料体系设计提供了科学依据。