Effect of aging temperature on microstructure and corrosion behavior of 6082 aluminum alloy

The effect of artificial aging temperatures on microstructure precipitation characteristics and corrosion behavior of extruded 6082 aluminum alloy had been investigated. Electrochemical measurements and microstructure characterization techniques were conducted on the alloy with under-aging, peak-aging and over-aging. The results show that the alloy had the maximum corrosion current density and corrosion depth under peak-aging, and the over-aging treatment optimized the corrosion behavior. The fiber texture in extruded alloy was the weak site of corrosion, and the Si particles distributed along the plastic deformation flow lines acted as a bridge to the propagation of corrosion cracks. The coarsening and dissolution of precipitates & beta;-- Mg2Si reduced the corrosion damage along the plastic deformation flow lines, leading to the change of corrosion model. The polarity change caused by & beta;-- Mg2Si de-alloying behavior was the main driving force for the development of IGC.