摘要：针对某型含预腐蚀损伤2系列航空铝合金，研究裂纹从腐蚀坑处萌生、小裂纹扩展、长裂纹扩展至断裂的过程。通过观测不同预腐蚀时间下腐蚀坑特征尺寸，分析了腐蚀坑形貌、深度、开口面积随预腐蚀时间的变化规律；通过复型法研究了腐蚀坑发展为小裂纹的过程，并对含预腐蚀损伤的铝合金进行空气与盐水环境下的裂纹扩展试验，结果表明：腐蚀坑深度随腐蚀时间的增长速度要比腐蚀坑面积增加的快；小裂纹扩展路径比较曲折，大部分裂纹形状近似Z字形扩展；无论是空气环境还是盐水环境下，疲劳长裂纹的扩展速率主要由应力水平决定，应力水平越高裂纹扩展速率越快，而预腐蚀损伤程度对长裂纹扩展速率的影响不显着。

　　关键词：航空铝合金，预腐蚀损伤，小裂纹，裂纹扩展

 Analysis of the crack initiation and propagation of a pre-corrosion aeronautical aluminum alloy
Wang Lei^*,+，Hui Li^*,+，Xu Liang^*,+，Zhou Song^+
*(Department of Mechanical and Electrical Engineering, Shenyang Aerospace University, Shenyang 110136,China )
⁺( Key Laboratory of Fundamental Science for National Defence of Aerouautical Digital Manufacturing Process，Shenyang 110136,China)

　　Abstract:The crack initiation and propagation including small cracks and long cracks from the corrosion pits of a 2 series pre-corrodedaeronautical aluminum alloy were analyzed. The changes of the corrosion pits' shapes, depths and openning areas were studied by observing the pits sizes. The replica method was utilized to investigate the small crack initation from the pits, and the long crack propagation tests both under the air and saltwater environments were implemented. Results show that the growth rate of the pits depths is faster than that of the pits areas, the small crack propagation paths are quite tortuous with Z-shaped lines. The stress levels have a stronger effect on the long cracks propagation rates both under the air and saltwater environments rather than the pre-corrosion defects.

　　Key words:aeronautical aluminum alloy, pre-corrosion defect, small crack, crack propagation

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