Abstract:In this paper, the multi-axial fatigue failure of pre-corroded 2050-T8 Al-Li alloy were investigated by 3d digital image correlation and scanning electron microscope, under different corrosion durations and different equivalent stresses. The fatigue damage evolution of the specimens was analyzed by combining strain maps and fatigue damage severity curves, to describe the macro-cracking behavior, and the micro-crack behavior of the specimens was explored based on SEM fracture morphology analysis. Experimental results show that the multiaxial fatigue damage evolution of the specimen is different under different corrosion durations and loading loads, and the nucleation time, number, size, and location of macro cracks are also different (even under the same conditions). Most macro cracks initiate at the bottom and side walls of the corrosion pits, and a few macro cracks initiate at the mouth of the corrosion pits. There are multiple microcrack initiation phenomena, and the expansion and merger of microcracks form macrocracks.