Susceptibility of Damping Behavior to the Solidification Condition in the As-Cast M2052 High-Damping Alloy

M2052 alloy is a MnCu based high damping alloy that shows high damping capacity and the superior workability. In the present work, the microstructure and damping behavior of the alloy in different solidification cooling rates are investigated with directionally cast alloy plate. For the variation of solidification cooling rate in the range of 250~10K/s, the secondary dendrite arm spacing of the cast alloy changes from 4 to 18mm and grain size varies in the range of 100~200mm except the surface regions and center regions in the cast plate. As compared to the worked and heat treated alloy, the as-cast alloy shows a high temperature damping above the average phase transformation temperature of the alloy irrespective to the solidification cooling rate. On the other hand, a higher damping peak is observed in the cast alloy which is attributed much to the twin boundary damping, however, the magnitudes of the damping peak are found to be varied corresponding to the respective solidification conditions.