Parent-phase twinning induced ultra-high damping capacity of Mn–20Cu–5Ni–2Fe alloy under directional solidification process

Abstract

Directionally solidified Mn–20Cu–5Ni–2Fe alloy under different pulling rates were investigated by means of dynamic thermal mechanical analysis, optical microscope, X-ray diffraction and scanning electron microscope. It has been found that the favorable microstructure can be tuned through adopting appropriate pulling rate during the process of directionally solidification to approach ultra-high damping performance by enhancing the mobility of twin and dislocation. It is disclosed that the microstructure characterized by regular arranged dendrites with fluctuated composition, single parent phase with favorable orientation, large low-angle misorientation grains, and micron-scaled twins with the low angle misorientation boundaries, can leads to a substantially increase of twin boundary IF up to 2 times higher than the present ordinary manufacturing process. The result has important guiding significance for the research and preparation of ultra-high damping Mn–Cu based alloy.