The effect of grain size on the damping capacity of Fe-17 wt%Mn

The grain size dependence of the damping capacity of Fe-17 wt%Mn steel was investigated. A high damping capacity was measured in the ultra-fine grained steel, despite its lower volume fraction of epsilon martensite and lower density of a variant boundaries and epsilon/gamma phase boundaries. Dilatometry of the ultra-fine grained Fe-17 wt%Mn steel revealed that the epsilon gamma phase transformation was largely suppressed. The features of the damping spectra were related to the anti-ferromagnetic transition in the gamma phase, the thermo-elastic epsilon gamma phase transformation and the motion of grain boundaries in the ultra-fine grained microstructure. The damping spectrum of the ultra fine grained Fe-17 wt%Mn steel was dominated by grain boundary damping effects.1193sciescopu