(北京有色金屬研究總院 國家有色金屬復(fù)合材料工程技術(shù)研究中心，北京 100088)
摘 要: 采用粉末冶金法制備15%(體積分?jǐn)?shù))SiCp/2009Al復(fù)合材料，研究該材料的微觀組織、力學(xué)性能、高周疲勞性能以及疲勞斷口形貌。結(jié)果表明：在SiCp/2009Al復(fù)合材料的疲勞短裂紋擴(kuò)展階段，SiC顆粒及其表面包覆的2009Al薄層在裂紋擴(kuò)展面上形成“丘陵”狀形貌，使疲勞斷口的粗糙度增大，裂紋的閉合效應(yīng)也隨之增大；同時“丘陵”狀形貌可以引發(fā)疲勞裂紋擴(kuò)展路徑偏析，使裂紋擴(kuò)展的有效驅(qū)動力減小并使裂紋擴(kuò)展路徑增加；上述裂紋遲滯效應(yīng)使SiCp/2009Al復(fù)合材料在短裂紋擴(kuò)展階段具有較高的疲勞裂紋擴(kuò)展抗力。
關(guān)鍵字: SiCp/Al復(fù)合材料；疲勞短裂紋擴(kuò)展；裂紋閉合；裂紋偏析
（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
