A study of the ultrahigh damping capacities in Mg-Mn alloys

This study shows that Mg-Mn alloys exhibit high strain-dependent damping values, which are much better than that of pure Mg in the high strain region. The high damping capacities of these alloys are attributed to the dislocation that connects to the dispersed alpha-Mn. However, excessive alpha-Mn creates an obstacle dislocation effect, which leads to the decrease in damping capacities because of the tangled dislocations. This conclusion is confirmed by the G-L theory and TEM images. Meanwhile, the dispersed phase hampers the increase of damping peaks of temperature-dependent damping capacities, and the a-Mn aggregate at grain boundaries can hinder them from sliding. The results of this study will be useful for the further development of high-damping Mg alloys. (C) 2012 Elsevier B.V. All rights reserved.