MICROSTRUCTURE OF SUPERCONDUCTING CABLE COMPONENTS

Abstract

Using atomic force, optical and electron microscopy methods, the changes in the
microstructure and phase composition were investigated for the alloy Nb47%Ti used for the manufacture of
superconducting cable employed as current-carrying elements in the magnetic system for International
Thermonuclear Experimental Reactor. The test samples were prepared from the superconducting wire at an
intermediate step of the drawing process for the area reduction Ø1.3→Ø1.2 mm. The effect of cold drawing
and intermediate annealing on the properties of as-worked Nb-Ti alloy was assessed. Local strain zones were
found to occur in the rupture area. The shape and chemical composition of Nb-Ti wire was examined for both
a defect-free area and the rupture area. A Nb diffusion barrier was found to occur in the copper matrix of NbTi wire.