Microstructural Evolution and Mechanical Properties of As‐Cast and As‐Extruded Mg–14Li Alloy with Different Zn/Y and Zn/Gd Addition

Herein, the effects of Zn/Y and Zn/Gd addition on microstructural evolution and mechanical properties of the superlight Mg–14Li‐based alloy are investigated. The results show that Mg–14Li‐based alloys are characterized by predominantly single β ‐Li phase. Zn/Y addition leads to the introduction of homogeneous distribution of Mg 3 Zn 3 Y 2 (W phase), Mg 2 Zn 11 , and MgLiZn phases. With the strengthening effect of grain refinement and a large number of precipitates, the mechanical properties of Mg–14Li‐based alloy are improved, whereas MgGd 3 , MgGd, Mg 2 Zn 11 , and GdZn 5 phases appear with the addition of Zn/Gd, which enhance the Mg–14Li‐based alloy significantly due to grain refinement strengthening, the second phase strengthening, and solid solution strengthening. After hot extrusion, dynamic recrystallization (DRX) significantly refines β ‐Li into equiaxed grains, and broken precipitated phases are distributed along the extrusion direction. Mechanical properties of those alloys are improved because of grain refinement and distributed precipitates.