Microstructures and Mechanical Properties of Mg-6Li-6.5Gd-1Dy-2Zn Alloys

Extrusion Mg-6Li-6.5Gd-1Dy-2Zn alloy was prepared successfully by vacuum melting. The microstructures and mechanical properties of as-cast and as-extruded Mg-6Li-6.5Gd-1Dy-2Zn alloys were investigated. Extruding process refines the α (Mg) phase and β (Li) phase, and makes the Mg3X phase crushed and dispersed well. After heat treatment, Mg3X phase particles became finer and much more RE enriched phase particles formed in the matrix. These effects result in the improvement of mechanical properties of the alloys. In this study, after solution treated at 510°C for 3h and aged at 215°C for 99h, the as-extruded alloy exhibits the best mechanical properties, and the microhardness, ultimate tensile and elongation reach 103.0, 249 MPa and 34.8%, respectively.