Abstract: Effects of carbon and nickel on damping capacity and γ→ε martensite transformation behavior in Fe-Mn alloys were investigated with a reversal torsion machine,optical microscopy and TMA measurement.The carbon element increased the resistance of γ→ε transformation,made Ms temperature lower and decreased the volume fraction of ε martensite.Carbons pinning deteriorated the damping capacity by reducing the mobility of boundaries.Nickel element made the phase-transformation temperature lower,but did not cause the alloy damping capacity worse.