LAUSR

Abstract The surface residual stress as well as corrosion behavior of an Al-Zn-Mg-Cu alloy plate is investigated under various pre-deformation conditions via X-ray diffraction, transmission electron microscopy, laser scanning microscope, open circuit potentials and electrochemical impedance spectroscopy measurements. Results reveal that the major extent of residual stresses from quenching can be relieved by 2% pre-strain, while the surface residual stress condition transforms from compression to tension if pre-strain exceeds 4%. During aging, the dislocations introduced by pre-strain promote the nucleation of large η phase and accelerate the coarsening of η′ precipitates. With increasing the pre-strain level, the number density of coarse η phase both at grain boundary and within matrix increases, resulting in a decrease in the corrosion resistance. In addition, the immersion test reveals an acceleration of corrosion when tensile residual stress exists in the surface of plate.