Enhancing damping properties of Mg–Sn–Y alloys: The role of metastable clustering

The damping properties of Mg–Sn–Y alloys with varied Sn/Y atomic ratios and heat-treatment processes have been studied. In the as-cast state, the alloy with a Sn/Y ratio of 3:1 exhibits the highest damping property in the low strain region due to the low Y solid solution and small lattice distortion. After heat treatment with 480 °C and 24 h, the lattice distortion of the alloy with a Sn/Y atomic ratio of 1:1 is significantly reduced compared to the cast alloy, resulting in an ultra-high damping property in the low strain region (ε = 10−4, Q−1 = 0.023). This change in damping property is attributed to the presence of metastable clusters, which consume energy through atomic rearrangement, separation, and redissolution, thereby enhancing the damping property. However, excessively long heat treatment times or high temperatures are detrimental to the formation of these metastable clusters, leading to a decreased damping property.