Investigation on Ic(B, T), Hc2(T), and microstructure of internal-tin Nb3Sn wires

摘要

The magnetic field (in range 5-12 T) and temperature dependencies (in range 4.2-12 K) of the transport current density Jc(B, T) and temperature dependence of upper critical field Bc2(T) in internal-tin multifilamentary wires are presented. The Summers relations have been applied for evaluation of the experimental Jc(T) and Bc2(T) data. The fitting parameters C, Tcm(0), and Bc2m(0) has been defined as giving the best fit to the experimental data. The microstructure of Nb3Sn filaments has been investigated by SEM. The particular features of the diffusion processes in internal tin wires lead to formation of the specific Nb3Sn filaments microstructure associated with high critical current density which have been analyzed.