The use of mechanical alloying in the manufacture of multifilamentary superconductor wire

Mechanical alloying, a high energy ball milling technique, was used to process elemental metal powders. Multifilamentary Cu-Nb3Sn composites were formed by mixing the mechanically alloyed Nb/Sn powders with Cu powders, isostatically compacting the mixture, hydrostatically extruding to wire form, and diffusion reacting to form the A15 superconducting compounds from the mechanically alloyed powders. Superconducting transition temperature (Tc'S) as high as 18.0 K were recorded for uniaxially compacted and vacuum reacted MA Nb/Sn powders. It was determined that to optimize the critical current density (J sub c) of the composite wire. Nb and Sn powders must be processed in a 30 at . % Sn ratio. Nevertheless J sub c s as high as 800 amps/sq cm in an applied field of 3 Tesla were recorded.