Cu-stabilized 7-filament MgB2 wires by an internal Mg diffusion process

Abstract

Compared with the Powder-In-Tube (PIT) method, MgB2 wires fabricated through the Internal Mg Diffusion (IMD) method demonstrate superior superconducting properties. However, magnesium’s hexagonal close-packed (HCP) crystal structure presents challenges in introducing Cu stabilizers into wires, thereby constraining the thermal stability of MgB2 wires. In this investigation, we improved the fabrication process to produce four distinct hundred-meter-scale Cu-stabilized 7-filament MgB2 wires. Experimental results indicate that the composite wires’ maximum Cu/SC Ratio reaches 2.45. Introducing Cu stabilizers enables the wire to achieve a tensile strength of 393 MPa at room temperature. Furthermore, the critical current density Jc of the wire can reach 2.3 × 105 A/cm2 at 4.2 K and 4 T. Our research provides a reliable reference for further preparation of high-stability MgB2 wires.