Effect on Deformation Process of Adding a Copper Core to Multifilament ${\rm MgB}_{2}$ Superconducting Wire

Abstract

Abstract-Using the PIT method, multifilament wire with different packing strategies has been manufactured. In all, three types of wire have been investigated, a 19-filament configuration using ex-situ powder in an Fe-matrix and two 8-filament configurations in an Fe-matrix applying a copper core, one using in-situ and another using ex-situ powder. The effect on the annealing requirements during mechanical processing of adding such a copper core has been investigated. The results show that the number of required annealings drops by about a factor of one half with the addition of a copper core. This finding is supported by numerical simulations of the deformation process which indicate that tensile stresses are concentrated around the middle of the wire during the drawing process. As such, strategic packing of the multifilament configuration can reduce the need for annealing during the mechanical deformation process. It is also found that the multifilament configuration using in-situ powder requires less annealing than the ex-situ counterpart. This is most likely due to the fact that in-situ powder is more readily compacted than ex-situ powder.Index Terms-Magnesium diboride, superconducting composites, superconducting filaments and wires, superconducting materials mechanical factors.

Superconducting MgB2 Wire Drawing Considering Anisotropic Hardening Behavior and Hydrostatic Effect

“…Among the numerous pressure-dependent constitutive models [20][21][22][23], the Drucker-Prager Cap (DPC) model is widely used to simulate the fabrication process of powderbased superconducting wires to predict the powder density or analyze the effect of process parameters on powder density [24][25][26][27][28][29]. Shah et al [24] first built a model for the drawing process of the Bismuth-Strontium-Calcium-Copper-Oxide (BSCCO) superconducting wire using the DPC model to predict the powder density and the drawing force.…”