Temperature dependence of the damping capacity in Fe–19.35Mn alloy

The effects of ɛ-martensite and temperature on damping capacity of Fe–19.35Mn alloy were studied. The damping capacity was measured using reversal torsion pendulum with free decay method. The phase structures were determined using XRD. The microstructure was observed using SEM. The results indicated that the damping capacity of the alloy with a lot of ɛ-martensite was similar to the alloy without ɛ-martensite, so the high damping mechanism of Fe–Mn alloys was not determined by ɛ-martensite but by stacking faults. The moving mode of damping sources was realized by the moving of Shockley partial dislocations, and the variation of damping capacity with strain amplitude at different temperatures was in accord with the breaking away model of Shockley partial dislocations (G–L model). With the temperature increasing (25–280 °C), the damping capacity of Fe–19.35Mn alloy was improved greatly because of the effect of thermo-assisted unpinning, which decreased the binding force between Shockley partial dislocations and pinning defects, and increased the number of Shockley partial dislocations that could break away at certain strain amplitude.