Low Cycle Fatigue Properties of Fe-28Mn-6Si-5Cr-0.5NbC Alloy

In this study, we conducted a low-cycle fatigue testing in a Fe-28Mn-6Si-5Cr-0.5NbC (FMS) alloy and a SUS304 steel. The fatigue tests were made using a servo hydraulic fatigue testing machine of capacity 50 kN, at maximum total strain amplitudes (epsilon(ta)) of 2.0%, 1.4%, 0.9%, 0.6%. In the SUS304 steel, with decrease in applied strain amplitude, stress-strain hysteresis loop is reduced. On the other hand, the stress response of the FMS alloy is almost unchanged, irrespective of the applied strain amplitude. The rupture life of the FMS alloy is 4 times higher at epsilon(ta)=0.6%, and twice at epsilon(ta)=0.9% and at epsilon(ta)=1.4% than the SUS304 steel. In addition, the stress amplitude of the FMS alloy is 1.5 times higher at epsilon(ta)=0.9%, and twice at epsilon(ta)=0.6% than the SUS304 steel. The prolonged fatigue life of the FMS alloy is attributable to the reversible deformation associated with the transformation pseudo-elasticity that can reduce the accumulated strain.