Effects of Salt-Spray Corrosion on Fatigue Life and Tensile Properties of LY12 Aluminum Alloy in Different Damage States

Through drilling and room temperature immersion tests, different sizes of through-holes and corrosion damage on the surface of LY12 aluminum alloy components after aircraft service were prefabricated, and the mechanical properties and fatigue life of the pre-damaged samples after salt spray corrosion were analyzed. The results show that after immersion for 120 h+salt spray corrosion for 96 h, the edges of corrosion pits of the sample were dissolved, and the corrosion products were increased and loosened. The stress concentration caused by corrosion pits made the strength of the sample decreased by 6.4% compared with the base metal. After 96 h of salt spray corrosion, the effective cross-sectional area of through-hole samples decreased. The strength of the samples with ϕ0.5 mm and ϕ1.0 mm through-hole decreased by 11.3% and 15.5% lower than that of the base metal samples, respectively. With the increase of loading fatigue stress, the area of fracture crack propagation zone gradually decreased, and the crack propagation life was shortened, while the effect of cyclic salt spray for 48 h and 96 h on fatigue life was small.