Strain amplitude dependence of the damping capacity in Fe-17% Mn alloy

The damping capacity of Fe-17%Mn alloy depending on the ∈ martensite content represents three different trends in the range of 1×10-4 to 10×10-4 strain amplitude. A linear relationship between damping capacity and volume fraction of ∈ martensite is established from 1×10-4 to 3×10-4 strain amplitude. It implies that the stacking fault boundaries in ∈ martensite and the ∈ martensite variant boundaries dominantly give rise to the damping capacity. In the range of 4×10-4 to 6×10-4 strain amplitude, however, the variation of damping capacity with ∈ martensite content is very similar to that of relative length of γ/∈ interface. This result suggests that movement of γ/∈ interfaces is introduced as an additional damping mechanism above 4×10-4 strain amplitude. The damping behavior depending on the ∈ martensite volume percent in the 7×10-4 to 10×10-4 strain amplitude is nearly the same as that in the 4×10-4 to 6×10-4 strain amplitude range, except for the abnormally high damping capacity of the specimen with 35% of ∈ martensite. This is probably caused by microslip deformation in the austenite phase.