Extrusion procedure and microstructure properties of multi-filamentary MgB2 superconducting wires

Abstract:

For improving the combine strength among filamentaries and the density of superconducting cores in multi filamentary MgB2 wire, the traditional hot-extrusion method was introduced to the MgB2 wires fabrication process. MgB2 wire with the conducting structure of 180 cores was fabricated by the extrusion method. Compound billet is extruded from Φ64 mm to Φ20 mm in diameter with one pass extrusion. The extruded wire is fabricated to the final size Φ0.8 mm in diameter with cold drawing and mid-annealing process. Superconducting filamentary is uniformly distributed and the thickness of Nb diffusion barrier is also smooth without breaking points through the microstructure analysisof the wires at each fabrication stages. The hectometer MgB2 wires is fabricated successful by this method. The extrusion technique is promising for producing long MgB2 superconducting wires.