Fabrication of Nb/sub 3/(Al,Ge) wires by using Al-Ge gas-atomized powder

As the starting material of Nb/sub 3/(Al,Ge) precursor wires, gas-atomized Al-Ge alloy powder is very promising because of the fine Ge particle dispersion in the alloy powder. The hardness of Al-Ge alloy is relatively small and well-balanced with that of the pure Nb. Therefore, no intermediate annealing is technically required for drawing a 7 /spl times/ 220 /spl times/ 233-core Nb/Al-Ge multifilamentary wire. Furthermore, excellent J/sub c/-B performance without peak effects was obtained in the Nb/sub 3/(Al,Ge) tape specimens through the RHQ (rapid-heating/quenching) treatment. It may be caused by the synthesizing of A15 phases transformed from Nb-Al-Ge ternary supersaturated bcc phase. The present Nb/sub 3/(Al,Ge) tapes show a good agreement with Kramer's scaling law described as F/sub p/=A(B/sub c2/)/sup 2.14/b/sup 0.5/(1-b)/sup 1.46/, where A is temperature and field independent, and b=B/B/sub c2/.