【摘要】 采用扫描电镜原位观察方法研究了束丝SiC纤维增强铝复合丝在低频疲劳和静拉伸过程中的损伤过程。实验发现,经过较短时间的疲劳加载或在较低的载荷下就出现纤维裂纹,裂纹向基体方向扩展,没有明显的界面脱粘现象。损伤过程可分为三个阶段,包括以纤维裂纹萌生为主的损伤起始阶段、以纤维多次断裂和基体裂纹扩展为主的损伤累计阶段以及裂纹迅速扩展和主裂纹连接的失稳破坏阶段。根据剪滞模型计算的表观界面强度表明该复合丝为强结合界面。更多还原

【Abstract】 The fracture process in the fatigue and tensile test of SiC fiber reinforced aluminum composites was observed in situ with a scanning electron microscope. It is found there exist three stages of damage. The first stage is that the cracks initiate at the stressconcentrated sites caused by fiber fracturing, which increases as the load cycles increase. The second stage is characterized by multicracks in each fiber and extension of cracks. The last stage indicates the coalescence of cracks and the formation of a main cracked plane. No fibermatrix interface debonding was observed during the fracture process. The apparent interfacial bonding strength evaluated in terms of a shear lag model indicates a strong interfacial bonding.更多还原