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Among existing superconducting technologies, niobium-titanium superconducting alloy is the most commonly used superconducting material.

The Nb-Ti alloy with a mass ratio of nearly 1:1 has good superconducting properties. Its superconducting critical transition temperature Tc=9.5K can operate at liquid helium temperature. It transmits under a 5T (50,000 Gs) magnetic field. Current density Jc≥105A/cm2 (4.2K); the highest application field can reach 10T (100,000 Gs) (4.2K).
The alloy also has excellent processing properties, and superconducting wire and strip products can be obtained through traditional smelting, processing and heat treatment processes.

Therefore, after research began in the 1960s, it quickly entered industrial-scale production.
The annual output of the United States reached 100 tons in the late 1970s; China also built a trial production line around the 1980s.
Practical Nb-Ti superconducting materials are mostly simple binary alloys containing 35% to 55% Nb; some tantalum and zirconium can be added to improve superconducting properties.

Due to superconducting stability, Nb-Ti superconducting materials often use pure copper, pure aluminum or copper-nickel alloy as the base material, and are embedded with multiple Nb-Ti thin cores to form a composite multi-core superconducting material.

A superconducting wire can contain dozens to tens of thousands of Nb-Ti cores, with a minimum core diameter of 1 μm.
In addition, depending on the use occasion, multi-core wires are often twisted and transposed to reduce losses and increase electromagnetic stability.

The basic processing technology of Nb-Ti superconducting materials is: using a consumable electric arc furnace or plasma furnace to smelt pure titanium and pure niobium into alloy ingots, then hot-extrude them into billets, and hot-roll and cold-draw them into bars; The Nb-Ti alloy rod is then inserted into the oxygen-free copper tube as the base material and compounded into a single core rod; and after multiple composite assembly, it is processed into multi-core Nb-Ti superconducting wires and strips.

The material needs to undergo multiple large-scale cold working (processing rate above 90%) and low-temperature (below 400°C) aging heat treatment to enable the superconductor to obtain sufficient effective pinning centers and improve the superconducting performance of the superconducting material.

Due to the zero resistance effect of superconductors, which brings no Joule heat loss, and the ability of Nb-Ti superconductors to carry very high transport currents under strong magnetic fields, Nb-Ti superconducting materials are particularly suitable for electrical engineering applications with large currents and strong magnetic fields. field application.

For example: high-field magnets, generators, electric motors, magnetic fluid power generation, controlled thermonuclear reactions, energy storage devices, high-speed maglev trains, ship electromagnetic propulsion and power transmission cables, etc.

So far, the most successful applications of Nb-Ti alloy superconducting materials are: large cyclotron high-energy accelerators with a diameter of more than 1km and magnetic resonance imaging diagnostic instruments widely used in the medical sector.

Although scientists discovered copper-oxide high-temperature superconductors that can operate at liquid nitrogen temperature (77K) in the mid-1980s; niobium-titanium alloy superconducting materials rely on their unique excellent processing properties and good low-temperature superconducting properties, and are relatively inexpensive. Cost and decades of research, production and application development experience, niobium-titanium alloys are still the most important practical superconducting materials in the world today.