EFFECT OF DEFORMATION OF PARAMETERS ON INTERFACE MORPHOLOGY OF SILVER-SHEATHED HIGH-TEMPERATURE SUPERCONDUCTOR TAPES

We have produced a series of Ag sheathed BiSrCaCuO tapes with a systematical variation of some of the deformation parameters to investigate effects on the distortion of the sheath-core interface, which often shows a wavy morphology (''sausaging''). The increase of the powder density has been measured directly by monitoring the volume of the tapes during the deformation. Using silver particles as a ''tracer'', the non-uniform, wavy powder now can be observed also inside the bulk oxide core. We develop a simple model of the deformation process, based on a relaxation concept, and compare its quantitative predictions with our experimental results and with those of other groups.