Superconducting Properties of Reacted Mono- and Multifilament MgB2 Wires With Respect to Bending Diameters Using a Custom-Made Bending Test Probe

In this paper, the superconducting properties of reacted mono- and multifilament MgB2 wires were investigated with regards to the bending diameter via a three-point bending test using a lab-made bending test probe. The wires were manufactured by Kiswire Advanced Technology Co., Ltd. According to the results of the bending test, the tolerable bending diameters for mono- and multifilament MgB2 wires were 30 and 160 mm, respectively. In addition, the multifilament wire at a bending diameter of 150 mm showed the existence of a resistive zone caused by the “disconnection” of the MgB2 filaments due to microcracks developed across the entire wire along the transverse direction of the filament. Monofilament wires have the potential to be utilized in most superconducting applications in terms of bending diameter, whereas the bending properties of multifilament wires require improvement to facilitate the design and fabrication of multifilament MgB2 magnets.