The microstructure and damping capacity of Fe–18·39Mn alloy after equal channel angular pressing (ECAP) and annealing treatment were studied. The damping capacity was measured using reversal torsion pendulum. The microstructure was observed using SEM and TEM. The phase structures were determined using XRD. The results indicated that the damping capacity of Fe–18·39Mn alloy all vanished after ECAP and annealing at 600°C, increased rapidly at 700°C, reached the maximum at 900°C and then decreased at 1000°C. All these were ascribed to the change of the size of ϵ martensite plates.
