Effect of Al Composition on the Corrosion Resistance of Mg-14 mass% Li System Alloy

Abstract

Mg-Li system alloys have poor corrosion properties, especially cold-rolled sheet leads to exfoliation corrosion as a result of long-term immersion test. Addition of aluminum element to Mg-14 mass% Li alloy could be suppressed the occurrence of exfoliation corrosion. However, excess addition of aluminum to Mg-14 mass% Li alloy causes the degradation of corrosion resistance. In this study, the composition of aluminum in Mg-14 mass% Li was optimized to improve the corrosion property. 3 mass% of Al addition could be suppressed the corrosion rate because enough aluminum element dissolved into matrix and precipitation of the second phase was inhibited.

Fig. 2 Initial microstructures of homogenized Mg-14 mass% Li- x mass% Al alloys. (a) Mg-14Li-1Al and (b) Mg-14Li-2Al, (c) Mg-14Li-3Al and (d) Mg-14Li-5Al.