Novel cast-aged Mn-26.0Cu-2.0Ni-2.0Fe-2.0Zn-3.0Al (wt.%) alloy with good damping capacity and high usage
temperature has beenwell designed and developed in this work,which can act as a promising candidate toward
engineering applications. The microstructure, damping capacity and usage temperature were investigated systematically
by X-ray diffraction, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy,
and dynamic mechanical analyzer. The results show that heat treatment has a significant influence on the
damping capacity and usage temperature of as-cast MnCuNiFeZnAl alloy. Compared to the original as-cast
alloy with internal friction (Q−1) of 3.0 × 10−2 at a strain amplitude ε = 2 × 10−4 and usage temperature of
43 °C, the largest Q−1 (5.0 × 10−2) and highest usage temperature (70 °C) can be obtained simultaneously by
ageing treatment at 435 °C for 2 h,while homogenization-ageing, solution-ageing and overageing can just result
in the limited improvement of damping capacity and usage temperature. This is because the highest nanoscale
Mn segregation in Mn dendrites can be formed by spinodal decomposition during ageing, while carrying out
the homogenization or solution treatment prior to the ageing, as well as overageing treatment can cause the
weakening of Mn segregation at the macro/nano-scale and even the precipitation of α-Mn, thus leading to the
undesirable damping capacity and usage temperature.