Deformation-dominated texturing of superconducting filament in OPIT-fabricated Bi(Pb)SCCO-2223/Ag composite tapes

Texture formation in the ceramic filament of Ag/BiSCCO tapes was studied after cold rolling, uniaxial cold pressing and sintering by XRD /spl theta/-2/spl theta/ and /spl omega/-scan methods. More effective texturing of the outer layers as compared to that of the core interior was observed at the early rolling steps up to about 65% reduction in area. Texture inhomogeneity over the filament cross section is related to the inhomogeneous distribution of plastic deformation. Work hardening due to plastic deformation of non-sintered powder results in the broadening of X-ray peaks and an increase in microhardness. The recovery of these parameters occurs after annealing at the temperatures of 350-600/spl deg/C. The /spl omega/-scan studies revealed an improvement of c-axis texture by intermediate rolling compared to that in the as-sintered and pressed states. Deformation-induced texturing of the 2212-precursor is the main factor responsible for the texture of the final 2223-phase. The influence of Ag during the sintering stage is limited only to the outer layers of the filament; in the case of low preliminary deformation internal layers remained practically non-oriented.