Effects of Parent Phase Aging and Nb Element on the Microstructure, Martensitic Transformation, and Damping Behaviors of a Cu–Al–Mn Shape Memory Alloy

Abstract

It is recognized that both parent phase aging and element addition can dramatically enhance the comprehensive properties of Cu‐based shape memory alloys (SMAs). However, further in‐depth studies are still needed to clarify the detailed laws and mechanisms. Herein, the effects of parent phase aging and Nb element on the microstructure, martensitic transformation (MT), and damping behaviors of a Cu–Al–Mn SMA are systematically studied. It is found that both the damping at low temperatures and the height of internal friction peak arising from the reverse MT of the Cu–Al–Mn SMA can be improved by the parent phase aging due to the increase in interfacial mobility. When the aging temperature reaches 600 °C, the best damping can be obtained. Nb forms AlNb3 phase in the Cu–Al–Mn matrix. Due to the pinning effect of the AlNb3 phase on grain boundaries, the grains of the Cu–Al–Mn SMA can be remarkably refined. With the increase in Nb content, the damping of the 600 °C aged Cu–Al–Mn SMA increases first and then decreases. The associated mechanisms are discussed. This work aims to provide theoretical basis and technical support for the improvement of damping property of Cu‐based SMAs.