(北京有色金属研究总院 国家有色金属复合材料工程技术研究中心，北京 100088)
摘 要: 采用粉末冶金法制备15%SiCp/2009Al(体积分数)复合材料，并测试其旋转弯曲疲劳和轴向疲劳性能，采用扫描电镜观察其疲劳断口。结果表明：15%SiCp/2009Al复合材料具有良好的高周疲劳性能，疲劳裂纹萌生于试样表面中较大的SiC颗粒、金属间化合物颗粒以及一些“无特殊微观组织特征”区域；疲劳裂纹扩展以形成微孔与韧窝、形成撕裂脊、增强颗粒SiC开裂、增强颗粒−基体界面脱粘为主要形式；控制SiC颗粒粒度、优化SiC颗粒均匀分布于2009Al基体、保证SiC颗粒与基体具有良好的界面结合，这样的微观组织对 15%SiCp/2009Al复合材料的疲劳性能至关重要。
关键字: SiCp/Al复合材料；疲劳；微观组织；疲劳断口
prepared by powder metallurgy process
（National Engineering and Technology Research Center for Nonferrous Metal Composites,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The fatigue behavior of naturally aged powder metallurgy 15%SiCp/2009Al (volume fraction) composite was investigated. The fatigue lives were determined using load-controlled rotary bending and axial fatigue testing ,the fracture surfaces of samples were examined by scanning electron microscopy. The results show that the high-cycle fatigue properties of 15%SiCp/2009Al composite are superior, the fatigue cracks initiate from several different microstructural defects known as some fractured SiC particles with relatively bigger size at sample surface, intermetallics and so called no specific microstructural feather area. The voids and dimples, tear ridges, SiC particle fracture and SiCp-Al interface decohesion are the main mechanisms during fatigue crack propagation. The microstructure consists of the large size reinforcement, homogeneous distribution of reinforcement and well combination of reinforcement-matrix interface and plays a significant role for fatigue properties of 15%SiCp/2009Al composite.
Key words: SiCp/Al composite; fatigue; microstructure; fracture surface
