Experimental Investigation and Life Prediction of Fatigue Failure in 2050‐T8 Al‐Li Alloy With Dual Corrosion Pits

ABSTRACT

This study investigated the fatigue behavior of 2050‐T8 Al–Li alloy containing dual corrosion pits. Full‐field strain maps, damage severity factor curves, and fractographic analysis were integrated to characterize fatigue damage evolution, microcrack nucleation, and propagation under varying stress levels and pit distributions. Pit orientation and spacing dictated failure mode evolution: perpendicular pits accelerated fatigue failure relative to parallel pits. At small spacing, a strong synergistic effect promoted inter‐pit crack initiation; at intermediate spacing, competitive and cooperative interactions occurred; and at large spacing, failure was dominated by a single crack. Four crack nucleation sites were identified: micro‐pits (43%), corrosion bulges (25%), chapped features (19%), and corrosion tunnels (10%). A data‐driven model integrating mechanical and morphological parameters was developed to predict fatigue life, showing good agreement with the experimental results. Feature importance analysis further quantified the relative contribution of each input parameter.