The effects of contents of Zn and Gd elements and their mass ratios on microstructure and mechanical properties of as-cast and as-extruded Mg-8Li alloys were investigated.After extrusion,the precipitates are broken,and fine spherical particles with size about 100 nm are found to disperse in the β-Li.The bi-modal structure consisting of long-strip-like coarse-grain α-Mg and recrystallized fine-grain β-Li is formed.The strength and plasticity of the alloys are greatly improved after extrusion,and the YS and UTS increase with the increase of Zn and Gd contents.The Mg-8Li-8Zn-2Gd alloy exhibits an optimum comprehensive performance with the YS of 274 MPa,UTS of 283 MPa,and EL of 39.9％.The bi-modal structure strengthening consisting of the fine crystal strengthening of β-Li and texture strengthening of α-Mg,and the dispersion strengthening of precipitations are the main strengthening mechanisms.
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