Silicon Carbide Monofilament‐Reinforced Silicon Nitride or Silicon Carbide Matrix Composites
Silicon Carbide Monofilament‐Reinforced Silicon Nitride or Silicon Carbide Matrix Composites
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DOI：
10.1111/j.1151-2916.1989.tb06174.x
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发表时间：
1989-04
影响因子：
3.9
通讯作者：
Hironori Kodama;H. Sakamoto;T. Miyoshi
中科院分区：
文献类型：
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作者：
Hironori Kodama;H. Sakamoto;T. Miyoshi
采用热压法制备了SiC-单丝增强SiC或Si3N4基复合材料，并研究了其力学性能以及长丝和长丝涂层的影响。还研究了丝/基体界面摩擦应力与SiC单丝/Si3N4基复合材料断裂韧性之间的关系。结果，实验证实，在复合材料因长丝拔出而断裂的情况下，断裂韧性随着摩擦应力的增加而增加。另一方面，当摩擦应力太大（>约80 MPa）而无法拉出细丝时，复合材料的断裂韧性几乎相同，并且比Si3N4整体陶瓷的断裂韧性没有太大提高。研究发现，长丝涂层对 SiC 单丝/Si3N4 基体界面的摩擦应力以及复合材料的断裂韧性有显着影响。还通过由SEM和弯曲机组成的原位观察装置观察了弯曲加载和循环加载试验期间SiC单丝/Si3N4基复合材料中的裂纹扩展行为。可以清楚地观察到阻碍裂纹扩展的细丝效应。 300 次循环载荷应用后未检测到疲劳裂纹扩展。
SiC-monofilament-reinforced SiC or Si3N4 matrix composites were fabricated by hot-pressing, and their mechanical properties and effects of filaments and filament coating layers were studied. Relationships between frictional stress of filament/matrix interface and fracture toughness of SiC monofilament/Si3N4 matrix composites were also investigated. As a result, it was confirmed experimentally that in the case of composites fractured with filament pullout, the fracture toughness increased as the frictional stress increased. On the other hand, when frictional stress was too large (>about 80 MPa) for the filament to be pulled out, fracture toughnesses of the composites were almost the same and not so much improved over that of Si3N4 monolithic ceramics. The filament coating layers were found to have a significant effect on the frictional stress of the SiC monofilament/Si3N4 matrix interface and consequently the fracture toughness of the composites. Also the crack propagation behavior in the SiC monofilament/Si3N4 matrix composites was observed during flexural loading and cyclic loading tests by an in situ observation apparatus consisting of an SEM and a bending machine. The filament effect which obstructed crack propagation was clearly observed. Fatigue crack growth was not detected after 300 cyclic load applications.