Evaluation of the Fatigue Property of DI-BSCCO Ni Alloy Reinforced Tapes

Abstract

Type HT-NX series, DI-BSCCO tapes laminated with pre-tensioned nickel alloy foils for reinforcement, have higher strength than the other types of DI-BSCCO tapes. In this research, we measured the effect of cyclic tensile load of up to 10⁵ cycles on the I_c degradation of 4 kinds of HT-NX tapes and a spliced tape by the original fatigue test system. The results indicated that Ic of HT-NX series tapes survive up to 10⁵ cycles, if an applied cyclic maximum stress (stress ratio 0.1) is less than their own static irreversible stress. From observations of the same location of the longitudinal section during fatigue, a local crack from the BSCCO layer penetrating a few fatigued Ag pipes was found, while a crack in the BSCCO layer by static load with the same I_c degradation level was trapped by a Ag pipe. The damage to the Ag pipe is peculiar to the cyclic load.