三维连通网状SiC/Zr基非晶复合材料的组织与性能

Microstructure and mechanical properties of 3D-net SiC/Zr amorphous matrix composites

以多孔SiC陶瓷为增强体,采用压力-浸渗-快凝法制备了三维连通网状SiC增强Zr基非晶复合材料,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和能谱分析(EDXA)研究了预制体和复合材料的相组成和原始显微组织、界面形貌及断口形貌,探讨了网络结构陶瓷预制体的特性对复合材料组织的影响,以及复合材料中的界面对其力学性能的影响。结果表明,陶瓷预制体与Zr非晶复合后形成了具有双连续相的网络交叉结构,复合材料中陶瓷与非晶合金的界面处存在增强体成分Si与基体成分Zr之间相互扩散的扩散层,该扩散层厚度为1μm左右,界面结合机制主要为扩散结合和机械结合,适中的界面强度兼顾了复合材料的强度和韧性;增强体的断裂是复合材料断裂的主要机制,非晶合金发生粘性流动,在裂纹的扩展中起到了桥接的作用。

The 3D-net SiC/Zr amorphous matrix composites reinforced by porous ceramic were fabricated using pressure-infiltration-quenching method.The phase structure,interfacial morphology and failure surface were investigated by means of X-ray diffraction（XRD）,scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDXA）,and the effect of the 3D-net SiC preform on the structure of the composites and the effect of interfaces on mechanical properties of the composites were discussed.The results show that ceramic preform is composited with Zr to form cross-net structure with double continuous phase.The diffusion distribution of elements（Si and Zr）in interfacial field indicates that there is a diffusion layer between ceramic phase and the matrix with the thickness of about 1 μm.The interfacial bond mechanism of 3D-net SiC/Zr amorphous matrix composites includes mechanical combination and diffusion bond,and the strength of interface combining strength and toughness of composites is appropriate.The destroy of the 3D-net SiC is the main factor leading to the fracture of the composites,and viscous folw existing in the amorphous alloy acts as bridging agent during crack extension.