Study on high damping L12/D03 biphase Fe-27Ga alloys with near-zero magnetostriction and its damping mechanism

Abstract

A novel L12/D03 biphase Fe-27Ga alloy with both high damping (0.007, equivalent to a specific damping capacity (SDC) of 0.04) and the near-zero (∼−4 ppm) magnetostriction has been prepared by using an appropriate heat treatment process: annealing at 480 °C for 1 h. Here the L12 phase proportion is about 44.8%. More importantly, the damping mechanism of L12/D03 biphase Fe-27Ga alloy has been deeply studied based on the experiments of amplitude-dependent IF measurements with and without magnetic field, combined with the magnetostriction measurements. All the results indicate that for the L12/D03 biphase Fe-27Ga alloy, D03 phase with a magnetic damping plays a dominant role under a lower strain amplitude while L12 phase with a non-magnetic damping plays a main role under a higher strain amplitude. At the same time, the L12/D03 biphase Fe-27Ga alloy with more L12 phase has a higher damping capacity under a higher strain amplitude, which is mainly the non-magnetic damping contribution originated from the twin boundaries movement. This can provide a new way and design concept for high damping Fe-Ga alloys to satisfy more application requirements, such as micro-vibration field, strong vibration field, magnetic or non-magnetic field.