Preparation and characterization of Mg-6Li and Mg-6Li-1Y alloys

Mg-6Li and Mg-6Li-1Y (wt.%) alloys were prepared using permanent model casting method, and microstructure and mechanical properties were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy (OM), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), etc. The results showed that α-Mg and β-Li phases existed in both alloys, and there was also Y-enriched phase in Mg-6Li-1Y alloy. The composition of Y-enriched phase was near to the maximal solid solubility of Y in α-Mg phase. The ultimate tensile strength and yield strength of Mg-6Li-1Y alloy were improved to 112 and 107 MPa, respectively. The elongation of Mg-6Li-1Y alloy was greatly enhanced to 32% at room temperature, which was about eight times as great as that of Mg-6Li alloy. The strengthening effects of Mg-6Li-1Y alloy were attributed to the solid solution effect and precipitates both introduced by Y.