ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 24    No. 7    July 2014

Exfoliation corrosion behavior of 7050-T6 aluminum alloy treated with various quench transfer time
Feng-xuan SONG, Xin-ming ZHANG, Sheng-dan LIU, Qi TAN, Dong-feng LI
(School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The exfoliation corrosion (EFC) behavior of 7050-T6 aluminum alloy treated with various quench transfer time after solution heat treatment was investigated by standard EFC immersion tests, strength loss measurements after EFC tests and electrochemical impedance spectroscope (EIS) technique. The results showed that EFC resistance of the alloy decreased with increasing quench transfer time. Backscattered electron scanning electron microscope (SEM) together with transmission electron microscope (TEM) observations revealed that the coverage ratio and microstructure of precipitates at grain boundary area are the most important factors which influence the EFC susceptibility of the alloy, while precipitate-free zone (PFZ) near grain boundary has no or only a minor effect on it. In addition, galvanostatic measurements of the alloy present a good correlation between EFC resistance and transients in potential. The cumulated number of transients in potential can be used to evaluate EFC resistance of the alloy.
Key words: 7050-T6 aluminum alloy; thick plate; exfoliation corrosion; quench transfer time; electrochemistry
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)