Bi-Sr-Ca-Cu-O conductors and magnets at high stress-strain levels

We focus on a react and wind Bi-2223 conductor with a pure silver matrix. T he stress-strain-critical current relation is determined for coils with a u niform stress distribution, at 4.2 K and 19 T. Somewhat surprisingly, the c oils fail at a Lorentz force induced strain value close to the value for un i-axially loaded straight samples. This implies that bending strain is only partially retained due to the plastic nature of the pure silver matrix. Al so, a double-pancake coil with a 15 mm winding thickness, resulting in a no n-uniform stress distribution, is tested at 4.2 K and 19 T. The coil curren t is cycled with increasing peak values and the onset and evolution of crit ical current degradation in the coil is shown. (C) 2001 Elsevier Science B. V. All rights reserved.