Structure and Mechanical Properties of Composite Semifinished Products for Nb 3 Sn Superconductors

The structure and mechanical properties of composite Cu/Nb/Sn rods of various designs used in the fabrication of multifiber Nb3Sn superconductors prepared by the internal tin source method are studied. It is shown that, upon reaching a high degree of deformation (ln  μ ~ 9), the tensile strength of the rods is ~700 MPa, while the plasticity drops to 2%. The structural features of the fracture surface of composite semifinished products are studied. The results will be used in the development of technological modes for the fabrication of Nb3Sn superconductors.