Experimental study of corrosion behavior on 7005 aluminum alloy under acidic 3.5 wt% NaCl environment

Abstract

AbstractThe corrosion failure behavior of 7005 aluminum alloy is a critical issue in the durability studies of vessels operating. In this study, the corrosion behavior of aluminum alloy 7005‐T4 in 3.5 wt% NaCl solution with pH 2, pH 4, and pH 6 was investigated by surface observation, electrochemical, and mechanical testing. The experiment results that the corrosion susceptibility is more at a solution of pH 2 compared with that at pH 4 and pH 6. The maximum depth and width of corrosion pits increase linearly with aggravation of corrosion. In addition, the probability distribution of the corrosion pit depth in each corrosion environment, which generally follows a Lognormal distribution, is statistically analyzed. The tendency of stress−strain curves at the elastic−plastic transition stage indicated that corrosion has an effect on mechanical performance, and revealed that corrosion promotes the advance of the plastic deformation stage. Fractography indicated the presence of a quasi‐cleavage zone beneath the corrosion layer. The results provide theoretical guidance for safe service and design guidelines for 7005 aluminum alloy.