Fine structural characterization of the elements of a Nb-Ti superconducting cable

Abstract A niobium-titanium alloy (Nb + 47%Ti) superconducting cable that acts as a current-carrying element in the magnetic system of the international thermonuclear experimental reactor (ITER) has been subjected to cold deformation by drawing. Its microstructure, phase composition and properties have been monitored via atomic force microscopy, electron microscopy and optical microscopy methods at the intermediate stage of cold drawing upon the transition of O1.3 → O1.2 mm. Plastic deformation centers are established to be localized at the breakage sites of the cable, and the shape and chemical composition of Nb-Ti fibers are determined at the defect-free region and breakage sites, as well. A partial lack of diffusion Nb barriers is also highlighted around Nb-Ti fibers at the breakage sites.