Simultaneous improvement of strength and damping capacities of Mg-8Li-6Y–2Zn alloy by heat treatment and hot rolling

Mg-8Li-6Y–2Zn alloy with high damping capacity and adequate strength was prepared by heat treatment and hot rolling. Combined with density of states (DOS) calculation and microstructure characterization, the mechanical properties and damping capacities of Mg-8Li-6Y–2Zn alloy in different states were systematically investigated. The as-cast alloy is mainly composed of coarse dendritic and granular (Mg, Zn)24Y5 phase. 18R-type long-period stacking ordered (18R-LPSO) phase, is introduced into the alloy after heat treatment at 500 °C for 6 h, which can effectively improve the strength and elongation of the Mg-8Li-6Y–2Zn alloy. After hot rolling, the dynamic precipitation of the nanoscale (Mg, Zn)24Y5 phase consumes many solute atoms. The decrease in the number of solute atoms leads to an increase in the distance of dislocation movement, thereby increasing the damping capacity. Compared with the as-cast alloy, the tensile strength of the heat-treated + rolled alloy increased from 140 MPa to 210 MPa, and the damping capacity increased from 0.006 to 0.018.