MECHANICAL-PROPERTIES OF BI-2223 TAPES

Fundamental requirements for tapes to be implemented in power transmis sion cables include flexibility, in addition to current carrying capac ity. As a matter of fact, better and better critical current densities are being achieved on BSCCO 2223 tapes worldwide, and even though the best samples are still typically short and in many respects ''excepti onal'', it seems that the gap between actual and target values for Jc is becoming promisingly smaller, and first applications closer. It is therefore essential that also the mechanical performances of these int rinsically brittle composites are improved in order to meet the requir ements imposed by manufacturing, handling and installation operations. In this work, the mechanical behaviour of 2223 BSCCO tapes made by Po wder in Tube was systematically investigated. Stress-strain tensile te sts at room temperature and at 77 degrees K, bending tests, and critic al current versus strain measurements were carried out on tapes with p ure Ag sheath. The results are discussed in terms of a semi-empirical model specifically developed, which takes into account also the thermo -mechanical history of the samples.