This study investigated the relationship between Mn segregation, damping capacity, and mechanical properties of a Mn–Cu damping alloy after aging at different temperatures. The results showed that after aging, the alloy underwent spinodal decomposition, forming Mn-segregated regions, while α-Mn precipitates appeared at the grain boundaries. The microstructure resulting from spinodal decomposition promoted martensitic transformation, created twin boundaries, and enhanced damping capacity. As the aging temperature increased, the Mn content in the Mn-rich regions gradually rose, thereby raising the martensitic transformation temperature. The twin density first increased and then decreased, which may be attributed to the precipitation and broadening of the α-Mn phase along the grain boundaries of the Mn-rich regions when the aging temperature was too high. At an aging temperature of 425 °C, the tanδ reaches a maximum of 0. 05, and the martensitic transformation temperature reaches 100 °C, at which point the tanδ remains 0. 04. After aging at 425 °C, a preferred orientation along develops. The 001 orientation has the largest Schmid factor, which is most favorable for the reversible motion of twin boundaries under external stress, thus achieving the highest energy dissipation. To summarize, by promoting the creation of fine 011 twins by means of spinodal decomposition and by increasing the 001 oriented grain fraction through texture development, aging enhances the damping properties of the Mn–Cu alloy. In particular, the aging at 425 °C can provide the best combination of the microstructure and texture conditions, providing the highest damping performance in a wide temperature range.
Wu et al. (Wed,) studied this question.