Nb-Ti Alloy Superconductors—Present Status and Potential for Improvement

摘要: Nb-Ti alloys were first introduced for superconductivity about 15 years ago with the titanium-rich alloy Nb 65 wt.% Ti (Ti 22 at.% Nb). Compared existing Nb-Zr alloys, this possessed twin advantages of better ductility and greater compatibility copper. With realization in late sixties that many conductor instabilities could be eliminated by subdividing twisting superconductor, emphasis shifted to more ductile compositions Nb-Ti, gave way niobium-rich containing 45 Ti. Most development filamentary conductors then was stimulated high-energy physics (HEP), whose principal requirement pulsed accelerator magnets. The such magnets contains strands; each is small (<1 mm) 10- 15-μm-diameter filaments. critical current density, J c , optimized use at 5 T 4.2 4.5 K. By rather empirical methods, density standard United States 46.5 37 Nb) steadily developed reach 1800 2000 A/mm2 K fine-filament conductors.