Effects of Cu on microstructure, mechanical properties and damping capacity of high damping Mg–1%Mn based alloy

In this paper, a high damping Mg–1%Mn based alloy with good corrosion resistance and adequate strength was prepared by studying the properties of Mg–Mn alloys. The effects of Cu addition on microstructure, mechanical properties and damping capacity of Mg–1%Mn alloy were investigated. The results show that Cu addition remarkably reduces the grain size of Mg–1%Mn alloy and a new binary phase, Mg2Cu, can be identified, which segregates at grain boundaries in the form of divorced eutectic and worsens the tensile properties. Using a low strain amplitude, the damping capacities of Mg–Cu–Mn alloys show minor variation with increasing Cu content, while with a high strain amplitude, the internal friction decreases with the smaller grain size and increasing amount of precipitates. In addition, the temperature dependent damping behavior of the Mg–Cu–Mn alloys was also discussed.