The hot deformation behavior of 7A55 aluminum alloy was investigated at the temperature ranging from 300 ℃ to 450 ℃ and strain rate ranging from 0.01 s-1 to 1 s-1 on a Gleeble-3500 simulator. Processing maps were established in order to apprehend the kinetics of hot deformation and the rate controlling mechanism was interpreted by the kinetic rate analysis obeying power-law relation. The results indicated that one significant domain representing dynamic recrystallization （DRX） existed on the processing maps and lying in 410-450 ＆#176;C and 0.05-1 s-1. The conclusions of kinetic analysis correlated well with those obtained from processing maps. The apparent activation energy values calculated in the dynamic recrystallization （DRX） domain and the stability regions except dynamic recrystallization （DRX） domain were 91.2 kJ/mol and 128.8 kJ/mol, respectively, which suggested that grain boundary self-diffusion and cross-slip were the rate controlling mechanisms.
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.
