Mechanical and transport properties of Ag alloy/Bi-2223 superconducting tapes under axial fatigue loading

For the endurance evaluation of HTS conductors, the mechanical and transport properties of Ag alloy/Bi-2223 superconducting tapes subjected to high cycle axial fatigue loading were investigated at 77 K. The relations between the applied stress amplitude and the fatigue life (S-N curves) were obtained using the Ag alloy/Bi-2223 tapes and their transport properties were evaluated with the increase of repeated cycles at different stress amplitudes. The effect of the stress ratio, R, on the Ic degradation behavior under fatigue loading was also examined considering the practical application situation of HTS tapes. Fractographic observation was performed in order to understand the Ic degradation mechanism in fatigued Bi-2223 tapes.