Effect of Ca Content on the Mechanical Properties and Corrosion Behaviors of Extruded Mg-7Li-3Al Alloys

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg-7Li-3Al alloys was investigated. The results showed that the extruded Mg-7Li-3Al-xCa alloys consisted of alpha-Mg (hcp) + beta-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg-7Li-3Al-xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg-7Li-3Al-0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential E-corr of -1.48742 V-VSE, attributed to the formation of protective Al2Ca phases.