Title :
Effects of additive elements on continuous ultra-fine Nb3Al MF superconductor
Author :
Takeuchi, T. ; Iijima, Y. ; Kosuge, M. ; Kuroda, T. ; Yuyama, M. ; Inoue, K.
Author_Institution :
Nat. Res. Inst. for Metals, Ibaraki, Japan
fDate :
3/1/1989 12:00:00 AM
Abstract :
Nb3Al multifilamentary (MF) wire can be fabricated by the composite process using various Al-based alloy cores and pure Nb matrix. Additive elements of Mg, Ag, Cu and Zn harden the Al core preferentially and then improve the workability of the Nb/Al composite, permitting it to be cold-drawn into a wire with ultrafine Al-based alloy filaments (filament number: 1.8 million, diameter: about 0.1 μm). Reacted wires at 700-900°C show Tc of 15-16 K, μ0Hc2 (4.2 K) of 21-22 T and Jc (4.2 K, 10 T) of 1-1.5×109 A/m2. A two-stage reaction consisting of a reaction above 950°C and a subsequent reaction around 700°C is carried out to improve critical values; Tc and μ0Hc2 are increased to 17.4 K and 25.4 T, respectively. Excellent superconducting properties involving good strain tolerance (εirrev=1.3%) indicate that this Nb3Al is very promising for practical high-field superconducting cables
Keywords :
aluminium alloys; composite superconductors; copper alloys; critical current density (superconductivity); magnesium alloys; niobium alloys; silver alloys; superconducting critical field; superconducting transition temperature; type II superconductors; wires (electric); zinc alloys; 17.4 K; Nb3Al; Nb3AlAgx; Nb3AlCux; Nb3AlMgx; Nb3AlZnx; cold-drawing; composite process; critical current density; critical temperature; high-field superconducting cables; reacted wires; strain tolerance; superconducting wire; two-stage reaction; ultra-fine multifilamentary wire; upper critical field; workability; Additives; Aluminum alloys; Capacitive sensors; Copper alloys; Multifilamentary superconductors; Niobium alloys; Superconducting cables; Wire; Workability; Zinc;
Journal_Title :
Magnetics, IEEE Transactions on
