Effect of bisulfite (HSO3-) on the stress corrosion cracking (SCC) behavior of 7050-T7451 aluminum alloy in the thin electrolyte layer environment in the presence of Cl- is investigated. Addition of HSO3- inhibits the corrosion initiation but promotes the corrosion propagation and hydrogen uptake. With a quantitative calculation, the HSO3- is demonstrated to significantly facilitate the synergistic effect between stress, corrosion, and hydrogen during the in-situ tensile test, resulting in the change of the SCC controlling step from corrosion-induced hydrogen to mechanical-electrochemical-hydrogen interactions. The buffer effect of HSO3- plays a dominant role in the HSO3--induced acceleration of the SCC degradation.
Bibliographical noteFunding Information:
The authors wish to acknowledgement the financial support of the Ministry of Industry and Information Technology Project (No. MJ-2017-J-99 ), Natural Science Foundation of China (No. 51701102 ), the Major-Special Science and Technology Projects in Shandong Province ( 2019JZZY010360 ), and the Outstanding Youth foundation of Shandong Province ( ZR2022YQ44 ).
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- A: aluminum
- B: SEM
- C: atmospheric corrosion
- C: hydrogen absorption
- C: stress corrosion