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.