Properties and performance of high current density Sn-core process MF Nb3Sn

Commercial production quantities of Sn-core-processed MF Nb3Sn have recently been manufactured and delivered. The 1.73 mm (0.068") diameter strand contains 721 02, 2 micron filaments and 49% stabilizing copper protected by a diffusion barrier. Critical current density in the filament bronze region can be optimized to exceed 2×10⁵amps/cm²at 10 Tesla 4.2 K and 3.7 × 10⁴amps/ cm²at 14 Tesla 4.2 K. Critical current as a function of applied tensile strain has been measured at 14 Tesla 4.2 K on samples of this material drawn to 0.36 mm (0.014") diameter. The peak in the Jc-ε curve occurs at ε = 0.28% and Jc = 1.25 Jco.