Influence of Ca on mierostructure and corrosion resistance of Mg-14Li alloy

In order to improve the corrosion resistance of magnesium lithium alloy, Mg-14Li alloy with different content of Ca (0, 3, 5, 10wt.%) was prepared with a induction melting furnace. Electrochemical test and corrosion test were carried out in NaCI solution with different Cl^- concentrations. The results indicate that the microstructure of the Mg-14Li alloy with Ca consists of dendritic β phase and eutectic structure (β+CaMg₂). With the increase of Ca addition from 0, to 3, 5, 10wt.%, the corrosion resistance of the Mg-14Li alloy initially increases first and then decreases, and that of alloy with 3% Ca is the best. Therefore, the corrosion resistance of Mg-14Li alloy in NaCI solution can be effectively improved by adding proper amount of Ca. In addition, the concentration of Cl^- was one of important factors affecting the corrosion resistance of the Mg-14Li alloy, and the influence of Ca was slighter than that of Cl^-.