Field and temperature dependences of critical current density in rapid quenched and transformed Nb/sub 3/Al multifilamentary conductors

Magnetic field and temperature dependences of J/sub c/ are measured for rapid quenched and transformed Nb/sub 3/Al multifilamentary wires that were fabricated by the Jelly-roll (JR) and Rod-in-tube (RIT) processes. The J/sub c/ in the transformed JR wire was much larger than that of conventional JR processed wires and also the transformed RIT processed wire. The scaling curve for the J/sub c/-B-T characteristics are given by a temperature scaling law, which agrees well with the experimental results in wide temperature and field ranges. The scaling curve enables us to evaluate J/sub c/ at low magnetic field and low temperature, for instance, J/sub c/ at 10 T, 4.2 K is estimated as 4700 A/mm/sup 2/. The main pinning source would be grain boundaries, because of the small grain size (several tens nm) and its high density.