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

Abstract

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 α-Mg (hcp) + β-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 Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.

Keywords

• mg–7li–3al alloy
• extrusion
• mechanical properties
• corrosion