Body-centered cubic (BCC) Mg–Li alloy can be effectively strengthened by with the addition of Al and Zn. However, adding excessive amounts result in reduced mechanical properties and damping capacity of the alloy during subsequent heat treatment and deformation. The effects of solution-hot rolling-aging on the mechanical properties and damping capacity of LAZ1333 alloy and LAZ1366 alloy were studied. The solid solution strengthening greatly increases the hardness of the alloy, but the ductility is extremely poor. The AlLi softening phase precipitated during the subsequent hot rolling and aging process greatly improves the ductility of the alloy, but the excess precipitation of in the AlLi softening phase and the solid solution of excess Zn element are not conducive to the substantial improvement of the strength and ductility of the alloy. Excessive addition of alloying elements is detrimental to the damping capacity of the alloy, but the damping capacity of the alloy can be significantly improved by depleting the number of solute atoms through subsequent ageing treatments. The UTS and FE of as-cast LAZ 1333 alloy are 111 MPa and 16.9%, respectively. The as-aged LAZ1333 alloy has the best mechanical properties and damping capacity, and the UTS and FE are increased by 65.8% and 89.3%, respectively, compared to the as-cast alloy, and the damping capacity increased from 0.011 to 0.015.

The development of MIG (metal inert gas) welding for five-series aluminum alloys primarily involves the improvement and optimization of welding processes. Building upon research findings regarding the enhancement of aluminum alloy properties through the use of scandium (Sc) and erbium (Er), our study incorporates Sc and Er into the welding wire to examine their impact on welding quality. The results show that the introduction of Er and Sc results in grain refinement from 47 µm to 29 µm and 31 µm, respectively. Grain refinement is mainly attributed to the heterogeneous nucleation of submicron-sized, coherent Al₃Er and Al₃Sc phases with L12 structure. The ultimate tensile strength (UTS), fracture elongation EI [%], and microhardness of joints welded with Er-containing and Sc-containing filler wires exhibit significant enhancements due to the refinement strengthening and dispersion strengthening. Joints welded with the filler wires containing Er and Sc display reduced corrosion current density and higher corrosion potential. The enhanced corrosion resistance comes from the formation of a denser oxide film and the equilibrium in the potential difference between the precipitated phases (Al₃Er and Al₃Sc) and the matrix. Filler wires containing Er and Sc have almost similar effects on improvements of the MIG welding joints.