The metallurgical design of Nb-Ti and Nb3Sn multifilament superconductors

Although the metallurgical properties are only one of a number of important concerns in the design of a useful multifilament magnet conductor, they are of basic importance both to the fabrication process and to the critical current density J
c
. In this paper we discus some of the implications of making certain metallurgical choices - for example in the Nb-Ti system high J
c
may be obtained over a range of alloy contents and for bronze route Nb
3
Sn conductors a variety of bronze to Nb ratios are chosen. Some of the consequences of the choice are explored with respect to the basic superconducting properties T
c
and H
c2
, the strongly structure sensitive property J
c
, the fabricability and the mechanical stability.