The composition of niobium-titanium superconducting alloy materials should meet the requirements of Tc, Hc2 and Jc as high as possible, generally in the range of Nb-(40% to 55%)Ti. The high Tc and Hc2 content and the high current carrying capacity of the superconducting material with a large number of precipitated phases can be obtained by this kind of gold component. There are six grades of niobium titanium alloy superconducting materials used in the world: Nb-44Ti, Nb-46.5Ti, Nb-48Ti, Nb-50Ti, Nb-53Ti, Nb-55Ti, etc., of which Nb-46.5Ti and Nb-50Ti are widely used alloy component grades.
A typical technology for the international industrial production of niobium-titanium superconducting materials is: The high uniform alloy ingot is processed and heat treated to produce a diameter of 3mm Nb-Ti rod, and an oxygen-free copper tube with a circular inside and hexagonal outside is placed on the jacket of the Nb-Ti rod. Hundreds to several dry or more of these composite rods are placed in an oxygen-free copper jacket with a diameter of 250 ~ 300mm, and after electron beam welding, they are extrudated into φ50 ~ 70mm composite rods at 500℃. The composite rod was drawn at room temperature at a pass rate of 20%, and aged at 350 ~ 420℃ for 4 ~ 6 times, and twisted to make the final size of φ0.5 ~ 1mm wire rod.
After the composition of niobium-titanium superconducting material is determined, its Tc and Hc2 values generally change little, and its Jc has a significant relationship with the microstructure produced by cold working-aging treatment. If the morphology, size, spacing and quantity of the cold working dislocation cell wall and the precipitated phase of the heat treatment can match the quantum magnetic flux, the maximum magnetic flux pinning force will be generated (see magnetic flux pinning theory), and the Jc of nib-Ti superconducting materials will reach the maximum value. In the production of niobium-titanium superconducting materials, the Jc of the materials is significantly improved by the single aging treatment after strong cold deformation. When the process of further cold deformation of niobium n (see multi-aging heat treatment technology of ferroniobium superconducting materials) is used for multiple times of cold deformation aging treatment and pure niobium titanium superconducting materials after the last aging process flow chart, the ideal microstructure (see microstructure of niobium titanium superconducting materials) can be produced, so that Jc can obtain a greater value.
