ADVANCES IN THE PROCESSING AND PROPERTIES OF YBA2CU4O8

High-filament-count, silver-sheathed composite wires of YBa2Cu4O8 were prepared by a metallic precursor route. The ductility of the metallic precursor enabled the manufacture of tapes containing up to 962,407 f ilaments, with filament dimensions as fine as 0.25 mu m thick and 1 mu m wide. The combination of thermal-mechanical treatment and fine fila ment dimensions resulted in significant biaxial crystallographic textu re. Transport critical current densities in the oxide filaments rts of 69.5 kA/cm(2) at 4.2 K in self-field with reduced weak-link behavior in an applied field were obtained. Critical current retention during b ending was shown to increase as filament count increased, with the hig hest filament-count mate ria I showing close to one percent critical b ending strain. These wires exhibited some of the best properties for a polycrystalline, sintered wire of YBCO in an applied magnetic field.