不同界面层体系对SiCf/SiC复合材料性能的影响

摘要

主要研究无界面层、裂解碳和氮化硼3种界面层体系对SiCf/SiC 复合材料力学性能的影响：首先，三维四向编织的SiC纤维预制体分别经过无界面层处理、裂解碳界面层制备（CVI工艺）和BN界面层制备（PIP工艺）3种不同工艺处理；以聚碳硅烷为原料，采用PIP工艺制备出3种SiCf/SiC陶瓷基复合材料工艺试验件；对工艺试验件的基本力学性进行研究，评价不同纤维预制体处理工艺对材料性能的影响。研究结果表明，无涂层复合材料样品的弯曲强度最高；具有PyC 涂层复合材料的弯曲强度略有下降，但断裂韧性较高；具有BN界面层的复合材料弯曲强度和断裂韧性均出现了较大程度的降低。3个样品力学性能的差别主要与纤维/界面层/基体之间作用力有关。本研究结果可以用于SiCf/SiC复合材料构件制造工作中，为制造工艺的初步筛选提供参考依据。%In this work, effects of interfacial layers on mechanical properties of SiCf/SiC composite have been studied. A SiCf/SiC composite without coat-ing and two SiCf/SiC composites with PyC (CVI) and BN (PIP) coating are prepared via PIP processing and their lfexural strength and fracture toughness are measured. The results show that PyC coating improves the toughness of SiCf/SiC composite effectively. And the BN coating on the surface of SiC ifber by PIP processing exists as amorphous compounds with B, N, Si, C, and O, which may lead to the damage of SiC ifbers.