Microstructure and Mechanical Properties of Mg-8Li-(0, 1, 2)Ca-(0, 2)Gd Alloys

A series of new Mg-8Li-xCa-yGd (x = 0, 1, 2; y = 0, 2; wt.%) alloys were prepared, and the microstructure and mechanical properties were investigated. The mechanical properties were characterized by tensile, compression and bending tests at room temperature. The results show that Mg-8Li-1Ca alloy is composed of alpha(Mg), beta(Li) and CaMg2 phases. In addition to the same phases in Mg-8Li-1Ca, there also exists CaLi2 phase in Mg-8Li-2Ca. In addition to the same phases in Mg-8Li-2Ca, GdMg5 phase is also formed in Mg-8Li-1Ca-2Gd alloy due to the addition of Gd. Both Ca and Gd have refining effect in the alloys, and the refining effect of Ca is better than that of Gd. The additions of Ca and Gd can improve the tensile strength and yield strength, but decrease the elongation and the bending strength. Comparing the mechanical properties of the investigated alloys, Mg-8Li-1Ca-2Gd possesses the best mechanical properties.