Abstract:In this paper, stress corrosion cracking (SCC) of 2050-T8 aluminum-lithium alloy with corrosion pit are experimentally investigated. Combined with acoustic emission, digital image correlation (DIC) and scanning electron microscopy, the damage evolution and failure rules of aluminum-lithium alloy under various conditions (single corrosion pit, double pits with different distances) is discussed. The experimental results indicate that the stress corrosion cracking process of pitted aluminum-lithium alloy can be divided into three stages: the pre-activation stage on the specimen surface; the initiation stage of stress corrosion cracks; and the propagation stage of stress corrosion cracks. Compared with the single corrosion pit condition, the crack propagation stage in specimens with double corrosion pit was shortened, which is attributed to the interaction and coalescence of cracks originating from two pits. The acoustic emission damage classification analysis based on artificial neural network shows that compared with the single corrosion pit, more corrosion behavior occurs in the process of stress corrosion cracking of the sample with double corrosion pit, due to the increase of corrosion area. The number of mechanical continuous signals appeared more and more quickly, indicating that the specimens with double pits produced more plastic deformation.

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