Effect of Grain Ultrafining on Corrosion Behavior of ZK60 Mg Alloy

Ultra-fine grained ZK60 Mg alloy was obtained by equal channel-angular pressing (ECAP), and the distribution of second phases was further adjusted by post-aging. Subsequently, localized electrochemical impedance spectroscopy (LEIS) and constant immersion test were used to analyze the influence of grain refinement and finer second-phase particles on the corrosion behavior of ZK60 Mg alloy. The results showed that the mass loss rate of the solution-treated ZK60 Mg alloy in 3.5%NaCl increased with ECAP passes, and the impedance first increased and then decreased with immersion time. Corrosion behavior of ultra fine-grained ZK60 Mg alloy was improved by post-ECAP aging, due to the better protective ability of corrosion product after the relief of internal stress and the redistribution of second phase.