THE MECHANICAL DEFORMATION PROCESS FOR PREPARING AG-SHEATHED BISRCACUO SUPERCONDUCTING TAPES

The mechanical deformation of Ag-sheathed ceramic superconducting tapes is a complicated and generally inhomogeneous process resulting in e.g. sausaging formation in the tape. In this paper we present a simple ''powder flow'' model describing the materials behaviour during the deformation process. The model implies that the final density of the ceramic core does not directly depend on the initial packing density, and the model explains how the sausaging formation depends on the flow direction. The model picture is also applied on aspects of crystal alignment during the mechanical deformation. The conclusions are supported by experimental results where mechanical deformation of Ag-sheathed BiSrCaCuO (BSCCO) tapes were studied.