Influence of large amount Zn on mechanical properties and corrosion resistance of 5083 hot rolled aluminum alloy

The influence of three kinds of alloy adding 0.3-1.8 wt% Zn on the mechanical properties and corrosion resistance of medium Mg content 4.0-4.5 wt% (5083 type) hot rolled alloy was investigated. The results showed that the addition of Zn content could further dissolve the second phases into the matrix. The hardness and tensile strength were reduced when annealing at 250 degrees C x 2 h. The mechanical behavior of the alloys showed a tendency that increases first and then decreases and the peak reached its maximum when 1.6 wt% Zn is added at both annealed and unannealed states. Through quantitative analysis, the improvement of mechanical properties mainly comes from dislocation strengthening and Al-Mg-Zn ternary strengthening phases. Meanwhile, with the increase of Zn content, the intergranular corrosion (IGC) of the alloy improved greatly after annealing at 250 degrees C x 2 h. The electrochemical corrosion potential (ECP) of the alloys increased first and then decreased.