Abstract
As-cast and extruded alloys of Mg-6Li-3Al-(0-5)Ca were prepared. The microstructure was characterized and the mechanical properties of these alloys were measured. Results show that the addition of Ca can inhibit the formation of AlLi and promote the formation of Al₂Ca. The Al₂Ca phase exists in the form of lamellar. The addition of Ca can also refine the microstructure of the alloys. The influence of Ca on the microstructure leads to the variation of mechanical properties. The decrease of AlLi phase and the increase of bone-like Al₂Ca are both infavorable for the mechanical properties of alloys, while the refinement effect of Ca improves the mechanical properties of alloys. Therefore, the optimal Ca addtion is 2 wt% for Mg-6Li-3Al alloy.

Key words
Mg-Li alloy; calcium; microstructure; mechanical properties

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