Abstract:The ultra-high strength Al-Zn-Mg-Cu alloy with strength of 800MPa has a promising application prospect in the aviation industry, and also a great effect on the structural lightweight, however, its application is limited at present due to its poor corrosion resistance. In this paper, the corrosion resistance of ultra-high strength Al-Zn-Mg-Cu alloy was controlled by controlling the quenching temperature of the colling water (quenching temperature for short). The microstructure, tensile mechanical properties, intergranular corrosion properties and exfoliation corrosion properties of the alloy after ageing were compared. It is found that increasing the quenching temperature promoted the formation of the intragranular and intergranular precipitates, and also promoted the intermittent distribution of the aged precipitation and the content of Cu in intergranular precipitations. The tensile strength at room temperature decreased by only 1.4%, but the intergranular corrosion depth decreased by about 50%. The exfoliation corrosion decreases from ED grade to PA-EA grade when the quenching temperature increased to 80 ℃, but decreased when exceeds 80 ℃. The analysis belives that when the proper quenching temperature is between 60 ℃ and 80 ℃, in which the precipitations increase the grain boundary potential and block the corrosion propagation channel. At the same time, the number and size of precipitations can be controlled, which didn’t cause significantly reducing of the mechanical properties.