Effect of solid-solution treatment on corrosion and electrochemical behaviors of Mg-15Y alloy in 3.5 wt.% NaCl solution

The effect of solid-solution treatment on corrosion and electrochemical mechanisms of Mg-15Y alloy in 3.5 wt.% NaCl solution was investigated by electrochemical testing, immersion testing and SEM observation. The results indicated that the corrosion resistance of Mg-15Y sample gradually deteriorated with immersion time increasing, which was consistent with the observation of corrosion morphologies. The solid-solution treatment decreased the amounts of second phase Mg24Y5. The Ecorr and corrosion rate of as-cast samples were both lower than those of solid solution-treated samples, and both increased with increment of solid solution-treated time. The corrosion mechanism was proposed for the galvanic, pitting and filiform corrosion which varied with the immersion time and solid-solution treatment.