The effects of secondary aging stress on electrochemical corrosion of Al-Zn-Mg-Cu aluminum alloy（7 A04）with two-stage stress aging were investigated in 3.5%NaCl solution by polarization curves and electrochemical impedance spectroscopy.The results indicate that with the increase of the stress in 0～300 MPa

the corrosion potential of 7 A04 aluminum alloys is increased and then decreased

while the self-corrosion current density is varied to the contrary.The alloy possesses the best electrochemical corrosion resistance with the aging stress of200 MPa

where the corrosion potential is-0.753 Vand the self-corrosion current density is 5.249×10-7 A·cm-2.Compared with stress-free and single-stage stress aging

the corrosion potential and AC impedance of 7 A04 aluminum alloy with two-stage stress aging are the higher and the self-corrosion current density is the lower

while its effect on pitting corrosion potential is not obvious.The change of precipitation phase distribution and size in 7 A04 aluminum alloy after stress aging are responsible for improving its electrochemical corrosion resistance.