试验测定了2种航空铝合金材料LD2CS和LD10CS的预腐蚀疲劳性能，根据试验观测现象和断口SEM分析结果，建立了新的腐蚀凹坑当量裂纹的抛物线模型，并推导了腐蚀凹坑当量裂纹的应力强度因子新公式，发展了疲劳载荷作用下航空铝合金材料的预腐蚀疲劳寿命估算方法。最后，采用本文的模型和算法对2种金属材料的预腐蚀疲劳性能进行模拟，发现本文提出的新方法的模拟结果与试验数据吻合良好，比传统的半椭圆模型和半圆模型有更高的预测精度。
关键词：铝合金；腐蚀；疲劳；SEM；凹坑；理想当量裂纹
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.
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