Engineering the precompression of Bi,Pb(2223): the influence of the geometry of the metallic matrix on the mechanical properties of tapes

At relatively low tensile strain (epsilon) levels, Bi,Pb(2223) tapes show a strain insensitive plateau in their L-c(epsilon) behavior, The "Irreversib le I-c Reduction Model" explains this regime as due to the irreversible dam age caused by the precompression of the ceramic filaments by the metal matr ix. In this paper we investigate whether this damage occurs predominantly d uring the cool-down from the reaction temperature to room temperature, or d uring the cryogenic refrigeration. Furthermore, we present L-c(epsilon) dat a on a range of tapes with different superconductor-to-matrix ratio and dif ferent tape geometry, showing how these factors influence the precompressio n. A modification of the "Irreversible I-c Reduction Model" is proposed to take into account "connected-grains" domains in the L-c(epsilon) behavior.