Effect of Al on the microstructure, corrosion behavior and mechanical properties of Mg-4Li

Purpose This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al. Design/methodology/approach The microstructure was characterized by using scanning electron microscopy and electron backscatter diffraction. The corrosion behaviors were measured by hydrogen evolution and potentiodynamic polarization tests. The mechanical properties were evaluated by tensile tests. Findings The addition of Al results in the precipitation of some Mg-Al phase and Al3Li phase particles, and the formation of some fine recrystallized grains. Originality/value Mg-4Li-3Al showed a higher corrosion rate than that of Mg-4Li, attributed to the precipitate particles in Mg-4Li-3Al causing microgalvanic corrosion and the change of grain orientation. The addition of 3 Wt. per cent Al increased the tensile strength by solid solution strengthening, precipitation strengthening, refinement strengthening and texture strengthening, whilst the elongation decreased by almost half.