关键词: 铝合金, 腐蚀, 疲劳, 扫描电子显微镜(SEM), 腐蚀凹坑, 当量裂纹

Abstract: In order to save the investigating costs and reduce the research periods of the helicopter materials, the theoretical simulation method is attempted to take the place of the corrosion fatigue tests in this paper. The fatigue behaviors of the pre-corroded LD2CS and LD10CS aluminum alloys were tested in this paper. A parabolic model was presented based on the observed test phenomenon and morphology characteristics of the Scanning Electron Microscope (SEM). The novel formulations were deduced base on linear elastic fracture mechanics to calculate stress intensity of equivalent crack of corrosion pits on the surfaces of pre-corroded aluminum alloys. An algorithm was developed to predict the fatigue life of the pre-corroded aluminum alloy subjected to fatigue loading. The fatigue behaviors of pre-corroded aluminum alloys LD2CS and LD10CS were modelled using the new model and algorithm proposed. Comparison shows good agreement between experimental data and predictions based on the new model and algorithm proposed, demonstrating that the fatigue behaviors of pre-corroded aluminum alloys can be predicted more accurately by the new parabolic model than by the traditional half elliptical and semicircle models.

Key words: aluminum alloy, corrosion, fatigue, Scanning Electron Microscope (SEM), corrosion pit, equivalent crack