Processing Parameters that Affect the Tolerable Bending Diameter of Reacted MgB2 Wires

Abstract

In this study, tolerable bending diameters of reacted MgB2 wires fabricated to produce varying outer sheath materials, numbers of MgB2 filaments, and sheath layer thickness were investigated. The result showed that the tolerable bending diameters of the MgB2 wires with Cu, Cu–Ni, and Monel sheaths were the same. This implies that the sheath material strength of these wires does not affect the tolerable bending diameter. In addition, mono-filament wires were more vulnerable to bending strain than multi-filament wires due to their porous microstructure. An increase in the sheath layer thickness of the MgB2 wires resulted in less degradation of the wires at high bending strains because the strain acting on the MgB2 filaments was reduced by the thick sheath layer. This study generally confirmed that the sheath layer thickness of the MgB2 wire is a key factor to increase the bending tolerance of the wire.