Fe-28Mn-6Si-5Cr-0.5NbC合金の低サイクル疲労特性と擬弾性

抄録

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 50kN, at maximum total strain amplitudes (ε_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 life to failure of the FMS alloy is 4 times higher at ε_ta=0.6%, and twice at ε_ta=0.9% and at ε_ta=1.4% than the SUS304 steel. In addition, the stress amplitude of the FMS alloy is 2 times higher at ε_ta =0.6 %, and 1.5 times higher at ε_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.