High-damping properties of Mn–Cu sintered alloys

The mechanical damping of manganese-rich Mn–Cu sintered alloys were investigated and compared to that of M2052 cast alloy. The damping of the sintered alloys consisting of α-Mn and γ-MnCu phases is of the order of 10−1 and insensitive to the frequency and temperature. Single phase γ-MnCu alloys, prepared by quenching from 1123 K, show two damping peaks; the large main peak is due to the twin boundaries and the small sub-peak is due to the fct ↔ fcc phase transformation. These peaks are larger than those observed for the M2052 alloy. The damping of Mn–Cu alloys aged at 723 K is insensitive to temperature.