Deteriorated corrosion performance of micro-alloyed Mg-Zn alloy after heat treatment and mechanical processing

The corrosion performances of the as-cast and solution-treated Mg-0.5Zn samples were investigated in 0.9% NaCl solution and compared. From the electrochemical measurement results and corrosion morphology observations, it is found that the corrosion resistance of Mg-0.5Zn deteriorated with the extension of solution treatment duration. The main reason was the formation of Fe-Si precipitates with higher Fe concentrations during heat treatment. The Fe-Si precipitates, especially the ones with high Fe contents influenced the corrosion initiation and propagation significantly. In regard of corrosion performance, the solution-treated and then extruded sample was also performing not as good as the cast and then directly extruded sample. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

The corrosion resistance of Mg-0.5Zn deteriorated with the extension of solution treatment duration due to the formation of Fe-Si precipitates. Fe-Si precipitates, especially those with high Fe contents, significantly influenced the corrosion initiation and propagation. Directly extruded cast samples showed better corrosion performance compared to solution-treated and then extruded samples.