Achieving high strength via solutes co-clustering and solvents redistribution in an ultralightweight BCC magnesium alloy

The microstructural features of a high-strength body-centered cubic Mg-Li-Al-Ag alloy are investigated and the strengthening mechanisms are discussed. The results show that obvious spinodal decomposition occurs in the alloy. Owing to the diffusion of Al atoms to Ag-vacancy pairs, co-clustering of Al and Ag is observed. The compositional redistribution of Li in the matrix reduces the interfacial lattice misfit and thus lowers the strain energy. Combinatorial spinodal strengthening with coherency strain hardening result in high strength achieved in the Mg-Li-Al-Ag alloy. The dual alloying strategy opens avenues for tuning the microstructure and enhancing mechanical properties of Mg-Li alloys.