Superconducting alloy of niobium-titanium superconelucting alloys

Niobium-titanium superconducting alloy is one of the most popular superconducting materials in the existing superconducting technology.

Nb-Ti alloy with mass ratio nearly l: 1 has good superconducting properties. Its superconducting critical transition temperature is Tc= 9.5K, which can be operated at liquid helium temperature. Its transmission current density is Jc≥105A/cm2(4.2K) under 5T(50,000Gs) magnetic field. 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 by traditional melting, processing and heat treatment processes.

As a result, the research started in the 1960s, and the industrial scale production soon began.

In the United States, annual production reached 100 tons in the late 1970s; China also built a trial production line around the 1980s.

The practical Nb-Ti superconducting materials are mostly simple binary alloys, containing 35% ~ 55% Nb. Some tantalum and zirconium can be added to improve the superconductivity.

Due to the reason of superconducting stability, Nb-Ti superconducting materials are commonly used as pure copper, pure aluminum or copper-nickel alloy as matrix materials, and multi-stranded Nb-Ti fine cores are combined to form composite multi-core superconducting materials.

A superconducting wire can contain tens to tens of thousands of strands of Nb-Ti core, the minimum core diameter of 1μm.

In addition, depending on the application situation, it is often necessary to twist and transposition the multi-core wires to reduce losses and increase electromagnetic stability.