Corrosion Behavior of Magnesium Alloy AP65 in 3.5% Sodium Chloride Solution

Magnesium alloy AP65 was prepared by melting and casting. The corrosion behavior of the as-cast and solid solution (T4)-treated AP65 alloys in 3.5% sodium chloride solution was investigated by corrosion morphology observation, immersion test, and electrochemical measurements. The results show that the second phase Mg17Al12 surrounded by a lead-enriched area distributes discontinuously along the grain boundaries in the as-cast AP65 alloy. The lead-enriched areas with high activity are susceptible to be attacked during immersion test and can act as places for preferential anodic dissolution. The corrosion resistance of the as-cast AP65 alloy can be improved after T4 treatment and the T4-treated alloy suffers general corrosion.