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用扫描电镜原位拉伸的方法研究了碳化硅纤维增强镁铝复合材料的机械性能 .通过对材料中裂纹的起源、扩展、断裂过程的观察研究 ,发现在拉伸状态下 ,裂纹最初起源于碳化硅纤维 ;在碳化硅纤维与基体结合较强时 ,裂纹首先在碳化硅纤维中扩展 ,同时裂纹附近的碳化硅纤维亦开始产生微观裂纹、镁铝金属基体发生塑性变形 ,最终断裂 ;而在碳化硅纤维与基体结合较弱的状态下 ,材料的韧性较高 .
The mechanical properties of silicon carbide fiber reinforced Mg-Al composites were investigated by scanning electron microscopy (in-situ tensile test). By observing the origin, propagation and fracture of the cracks in the material, it was found that the crack originated in Silicon carbide fibers. When the silicon carbide fibers are strongly bonded to the matrix, the cracks first expand in the silicon carbide fibers, and the silicon carbide fibers near the cracks begin to produce micro-cracks. The magnesium-aluminum metal matrix undergoes plastic deformation and finally breaks down. Silicon carbide fibers and the matrix combination of weak state, the higher the toughness of the material.