关键词: 铝合金, 腐蚀, 疲劳, SEM, 凹坑, 理想当量裂纹

Abstract: Abstract: The fatigue behavior of pre-corroded LD2CS and LD10CS aluminum alloys were tested in this paper. A practical parabolic model was presented based on the morphology characteristics of corrosion fatigue fractography, and novel formulations were deduced to calculate stress intensity of equivalent crack of corrosion pits on the surfaces of pre-corroded aluminum alloys by using linear elastic fracture mechanics. Afterwards, the algorithm was developed to predict fatigue life of pre-corroded aluminum alloy subjected to cyclic loading. Finally, fatigue curves for pre-corroded aluminum alloys LD2CS and LD10CS were modelled from the new model and algorithm, and the predictions were compared with the experiment data. It is showed that there is good agreement between experiments and predictions from the new model and algorithm proposed in this paper, and fatigue behaviours of pre-corroded aluminum alloys can be predicted more accurately by new parabolic model than by the traditional half elliptical and semicircle models.

Key words: aluminum alloy, corrosion, fatigue, corrosion pit,, SEM, idealized equivalent crack