Effect of Impurity Fe Concentration on the Corrosion Behavior of Mg-14 mass%Li-1 mass%Al Alloy

Abstract

Mg–Li system alloys with over 11 mass% Li have an excellent cold-workability in Mg alloys due to the bcc-structured crystal system. However this system alloys have poor corrosion resistance caused by Li solid-solution alloy. The corrosion resistance of conventional hcp-Mg alloys is influenced by the composition of impurity elements. Particularly, minute iron element deteriorates the corrosion resistance of Mg alloy and there is a threshold concentration on the corrosion rate in Mg alloys. In this study, the effect of iron element on the corrosion resistance of Mg–Li alloy was investigated by addition of iron. The corrosion resistance of Mg–Li with no Fe addition was higher than conventional Mg alloy. The corrosion rate of Mg–Li alloy increased with increasing iron concentration. However, there is no threshold iron concentration affected to the corrosion resistance on Mg–Li alloy.