Influence of adjusting the anodizing and aging sequences on the microstructure, fatigue property and corrosion resistance of anodized AA6082 alloys

Compared with the traditional anodization of aged aluminum alloy, a novel process was carried out by anodic oxidation of solid solution aluminum alloy, followed by aging treatment to optimize the interface's composition and microstructure, under which the thickness, hardness and modulus of the oxidation film wouldn't be influenced and the strength of base materials kept the same. As beta" precipitates cannot be formed in the subsequent aging process due to the consumption of Mg on the film-base interface, line defects caused by lattice distortion were avoided. Therefore, the stress concentration point in the fatigue process was reduced, and the fatigue property of the anodized material was improved from 89 MPa to 125 MPa. The anodizing of solid solution aluminum alloy helps the dispersion of Mg in the oxide film, which increases the self-corrosion potential of the oxide film from -0.97 V to -0.32 V and delays the occurrence of pitting corrosion during long-term immersion in 5 wt% NaCl solution.