Nouveaux supraconducteurs multifilamentaires de type A15 à base de niobium-aluminium présentant une densité de courant critique élevée à très haut champ.

When Nb/Al-X (X= Ge or Cu) microcomposite precursor wires were rapidly heated and quenched, disordered Nb3Al-based A15-phase filaments formed. With annealing at 750-800 °C, their superconducting properties improved drastically. The Nb3Al-based A15 wire, with Ge or Cu added, showed a maximum value of Tc= 19.4 or 18.2 K, and that of Hc2 (4.2 K)= 39.5 or 28.7 T, respectively, which are higher than the maximum values of Tc= 17.9 K and Hc2 (4.2 K)= 25.8 T for the rapid heating, quenching and transforming (RHQT)-processed Nb3Al wire without additional elements. In addition, the new superconductors showed higher Jc than that of the RHQT-processed Nb3Al multifilamentary wire in high fields.