Multifilamentary MgB2 Wires Prepared by an In Situ Powder-in-Tube Method

Abstract

MgB2 has become a commercially attractive material for technological applications for its particular superconducting properties. However, due to its brittleness to obtainwires, a metallic sheath is needed for drawing. In the presentwork, grade 2 titanium has been used as sheath material, and several multifilamentary wires have been prepared. The powder-in-tube method has been used to prepare the wires with the in situ variant, where the sheath is filled with the unreacted precursor powders (Mg and B). Different thermal treatments have been investigated including several intermediate treatments during the drawing process in addition to the final one. This last treatment is necessary to accomplish the synthesis and heal the cracks generated during the cold work. The superconducting properties were determined by magnetization measurements on a SQUID magnetometer, and the microstructure evolution was followed by TEM and SEM microscopy. Mechanical behavior is also evaluated.