LAUSR

Abstract The microstructure and corrosion behavior of as-homogenized Mg-xLi-3Al-2Zn-0.2Zr alloys (x = 5, 8, 11 wt%) were investigated. As the Li content increases from 5 wt% to 11 wt%, the alloys undergo a phase transition from α-Mg single-phase to α-Mg + β-Li dual-phase and then to β-Li single-phase. All alloys contain AlLi phase, filamentous AlLi phase exists in α-Mg matrix in eutectic form while round-like AlLi phase exists in β-Li matrix in granular form. The corrosion of as-homogenized LAZ532–0.2Zr and LAZ1132–0.2Zr alloys is mainly filiform corrosion and pitting corrosion, while that of as-homogenized LAZ832–0.2Zr alloy is mainly galvanic corrosion. As-homogenized LAZ832–0.2Zr alloy exhibits the best corrosion resistance attributed to the finer filamentous AlLi phase in α-Mg matrix, the smaller round-like AlLi particles distributed in β-Li matrix and along the α-Mg/β-Li interface, and the denser oxide film containing a small amount of Li2CO3.