By controlling the content of Ga and In in Al-Zn-Mg-Cu aluminum alloy

the effects of Ga and In on the degradation rate of the alloy were investigated.The constitutive equation of the degradation process was established.The mechanism of degradation reaction of the aluminum alloy was described by microstructure observation.The results reveal that the degradation rate of Al-Zn-Mg-Cu aluminum alloy can be controlled by adjusting the contents of Ga and In.When the content of Ga

In is increased from 2.01%、0.20% to 2.44%、0.52%

the degradation rate of the aluminum alloy is increased obviously from 0.049 8 mg/（mm

2

·h）to 3.402 0 mg/（mm

2

·h）

which are attributed to the occurrence of corrosion around the second phase containing Ga and In

then spreading to the substrate

and then the corrosion production cracked and easily falled off

promoting continuous reaction of aluminum and water.