Aging response and mechanism of dual-phase Mg-Li-Al-Zn alloy

In this work, the aging response and mechanism of dual-phase Mg-Li-Al-Zn alloy at various temperatures are investigated. The results show that the strengthening after quenching is primarily attributed to the immediate precipitation of the semi-coherent ∼Mg3Zn phase. The aging softening of the studied alloy is mainly caused by the rapid transformation of the strengthening ∼Mg3Zn phase to the softening MgLi(Al, Zn) phase, along with the coarsening of the α-Mg matrix and precipitates within β-Li matrix. Further analysis indicates that the quick precipitation and transformation of ∼Mg3Zn is a consequence of the high diffusion rate of solute atoms, resulting from dense vacancy concentration in the β-Li matrix. This research bridges a critical gap in the study of aging mechanism in the dual-phase Mg-Li-Al-Zn alloy, providing a theoretical basis for the development and application of high-performance and thermal-stable Mg-Li alloys.