New Nb3Al multifilamentary conductor and its application to high field superconducting magnet

We fabricated a new Nb3Al multifilamentary conductor through a transformation process from Nb-Al BCC supersaturated phases. The conductor shows the best values for TC, HC2(4.2 K), and overall JC(4.2 K, 20 T) of 17.6 K, 26 T, and 240 A/mm2, respectively. The overall JC(4.2 k) is 2-5 times larger than those of the commercially available Nb3Sn multifilamentary wires in fields of 0-26 T. The JC of the conductor also shows excellent tolerance to mechanical strain. We have already performed tests on several small coils in high fields using the new Nb3Al multifilamentary conductors. The results indicate that the new superconductor is very promising for high field applications. (orig.)