Quantitative study of the corrosion evolution and stress corrosion cracking of high strength aluminum alloys in solution and thin electrolyte layer containing Cl-

Abstract

Stress corrosion cracking (SCC) behavior of 2024-T351 and 7075-T651 in solution and thin electrolyte layer (TEL) are investigated by electrochemical and mechanical testing, surface observation, and hydrogen detection. Corrosion in TEL is more severe than that in solution as indicated by the higher corrosion coverage fraction, deeper corrosion attacks, serious local exfoliation, and higher hydrogen uptake content. SCC susceptibility of 2024-T351 in TEL is higher than that in solution, while the 7075-T651 is the opposite. Corrosion-induced hydrogen dominates the degradation in TEL environment, while the synergistic effect of stress, corrosion, and hydrogen controls the elongation loss in solution.