Remarkable Improvement of Damping Capacity of Mn–20Cu–5Ni–2Fe (at%) Alloy by Zinc Element Addition

Abstract

In this paper, the effect of Zn element addition on martensitic transformation and damping capacity of Mn–20Cu–5Ni–2Fe (at%, M2052) alloy has been investigated systematically by using X‐ray diffraction, optical microscopy, and dynamic mechanical analyzer. The results show that martensitic transformation and damping capacity have a crucial dependence on the addition of Zn element. It not only can markedly enhance the damping capacity of M2052 alloy at room temperature (internal friction Q −1 increases by ≈23% compared to M2052 without Zn as strain amplitude reaches 4 × 10 −4 ), but also reduces the attenuation of damping capacity effectively at elevated temperatures. This is mainly because the addition of Zn element can evidently increase the Gibbs free energy difference between γ parent phase and γ' phase produced by face centered cubic to face centered tetragonal (f.c.c‐f.c.t) phase transformation, and then raises the martensitic transformation and its reverse transformation temperatures, eventually leading to the apparent increase of amount of f.c.t γ' phase micro‐twins as damping source and the significant enhancement of damping capacity. It will be of great value for design and optimization of high‐performance M2052 damping alloy toward practical applications.