1.西北工业大学，西安 710072;2.西安航天动力研究所，西安 710010
1.Northwestern Polytechnical University，Xi’an 710072;2.Xi’an Aerospace Propulsion Institute，Xi’an 710100
通过控制沉积时间（5 h，15 h，30 h 和50 h）获得了不同PyC界面层厚度试样，随后采用先驱体浸渍-裂解工艺完成S5，S15，S30和S50-C/ZrC-SiC复合材料的制备工作，研究了PyC界面层厚度对C/ZrC-SiC复合材料弯曲、断裂性能影响规律及其作用机理。结果表明：随着沉积时间增加，PyC界面层厚不断增大，C/ZrC-SiC复合材料弯曲力学性能和断裂韧性均表现出先增大而后降低的变化规律。这主要由于PyC界面层厚度的增大，纤维损伤、基体热失配程度减弱，进而提高C/ZrC-SiC复合材料强度，但过大的PyC界面层厚度会降低纤维与基体的结合力和ZrC-SiC基体含量，最终导致C/ZrC-SiC复合材料强度的下降。而S30-C/ZrC-SiC复合材料因表现出较多“纤维桥连”、“裂纹偏转”和“裂纹分枝”现象，有利于消耗断裂能，最终表现出较好的断裂性能。
By controlling deposition time (5 h, 15 h, 30 h and 50 h), PyC interface with different thickness were obtained, and then S5, S15, S30 and S50-C/ZrC-SiC composites were prepared by precursor impregnation pyrolysis process. The effects of PyC interface thickness on the flexural and fracture properties of C/ZrC-SiC composites and its mechanism were studied. The results show that with the increasing of deposition time, the PyC interface thickness become bigger, and the flexural mechanical properties and fracture toughness of C/ZrC-SiC composites increase firstly and then decrease. This is mainly due to the release of fiber damage and fiber/matrix thermal mismatch with the increasing of PyC interface thickness, which will improve the strength of C/ZrC-SiC composites at last. But as PyC interface thickness become too larger, the bonding force between fiber and matrix and the content of ZrC SiC matrix will be reduced, which will eventually lead to the decrease of strength of C/ZrC-SiC composites. At the meantime, S30-C/ZrC-SiC composites exhibits more “fiber bridging”, “crack deflection” and “crack branching”, which are beneficial to the consumption of fracture energy, and therefore it shows better fracture properties.