(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%(体积分数)SiCp/2009Al复合材料，研究该材料的微观组织、力学性能、高周疲劳性能以及疲劳断口形貌。结果表明：在SiCp/2009Al复合材料的疲劳短裂纹扩展阶段，SiC颗粒及其表面包覆的2009Al薄层在裂纹扩展面上形成“丘陵”状形貌，使疲劳断口的粗糙度增大，裂纹的闭合效应也随之增大；同时“丘陵”状形貌可以引发疲劳裂纹扩展路径偏析，使裂纹扩展的有效驱动力减小并使裂纹扩展路径增加；上述裂纹迟滞效应使SiCp/2009Al复合材料在短裂纹扩展阶段具有较高的疲劳裂纹扩展抗力。
关键字: SiCp/Al复合材料；疲劳短裂纹扩展；裂纹闭合；裂纹偏析
（National Engineering and Technology Research Center for Nonferrous Metal Composites,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:15%(volume fraction) SiCp/2009Al composite was fabricated by powder metallurgy process. The microstructures, mechanical properties, high-cycle fatigue properties and fatigue fracture surfaces of composite were investigated, respectively. The results show that the mound-like shape enhancing the roughness of composite is formed by SiC particulate and 2009Al thin layer above it, and hence inducing crack closure in composite during small fatigue crack growth. And the mound-like shape also causes crack deflection in composite, thus reduces the crack propagation driving force and adds extra crack path. The enhanced fatigue crack resistance of SiCp/2009Al composite is explained by these two retardation effects mentioned above.
Key words: SiCp/Al composite; small fatigue crack growth; crack closure; crack deflection
