Niobium-titanium is an alloy

Alloy

An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

 of niobium

Niobium

Niobium or columbium , is a chemical element with the symbol Nb and atomic number 41. It's a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite...

 and titanium

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

, used industrially as a type II superconductor wire for superconducting magnet

Superconducting magnet

A superconducting magnet is an electromagnet made from coils of superconducting wire. They must be cooled to cryogenic temperatures during operation. In its superconducting state the wire can conduct much larger electric currents than ordinary wire, creating intense magnetic fields...

s. Normally as Nb-Ti fibres in an aluminium or copper matrix.

Its critical temperature

Superconductivity

Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...

 is 9.2 kelvin

Kelvin

The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

 and can remain superconductive until about 15 tesla

Tesla (unit)

The tesla is the SI derived unit of magnetic field B . One tesla is equal to one weber per square meter, and it was defined in 1960 in honour of the inventor, physicist, and electrical engineer Nikola Tesla...

.

It cannot withstand magnetic field intensity

Field strength

In physics, the field strength of a field is the magnitude of its vector value.In theoretical physics, field strength is another name for the curvature form...

 as high as the more expensive (and harder to use) niobium-tin

Niobium-tin

Niobium-tin or triniobium-tin is a metallic chemical compound of niobium and tin , used industrially as a type II superconductor. This intermetallic compoundis a A15 phases superconductor...

, but for most applications it is sufficient.

In 1962 the superior high-critical-magnetic-field, high-critical-supercurrent-density properties of Nb-Ti were discovered by T.G. Berlincourt and R.R. Hake, then at the Atomics International Division of North American Aviation, Inc. Those properties, together with affordability and easy workability, distinguish Nb-Ti alloys from thousands of other superconductors and justify their status as workhorse superconductors.

Superconducting magnets

A bubble chamber

Bubble chamber

A bubble chamber is a vessel filled with a superheated transparent liquid used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded the 1960 Nobel Prize in Physics...

 at Argonne National Laboratory

Argonne National Laboratory

Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...

 has a 4.8 meter diameter Nb-Ti magnet producing a magnetic field of 1.8 tesla.

About 1000 NbTi SC magnets were used in the 4 mile long main ring of the Tevatron

Tevatron

The Tevatron is a circular particle accelerator in the United States, at the Fermi National Accelerator Laboratory , just east of Batavia, Illinois, and is the second highest energy particle collider in the world after the Large Hadron Collider...

 accelerator at Fermilab

Fermilab

Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...

.
The magnets were wound with 50 tons of copper cables containing 17 tons of NbTi filaments. They operate at 4.5 K at fields up to 4.5 tesla.

1999: The Relativistic Heavy Ion Collider

Relativistic Heavy Ion Collider

The Relativistic Heavy Ion Collider is one of two existing heavy-ion colliders, and the only spin-polarized proton collider in the world. It is located at Brookhaven National Laboratory in Upton, New York and operated by an international team of researchers...

 uses 1,740 NbTi SC 3.45 tesla magnets to bend beams in its 3.8 km double storage ring.

In the Large Hadron Collider

Large Hadron Collider

The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....

 particle accelerator

Particle accelerator

A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...

 the magnets (containing 1200 tonnes of NbTi cable) are cooled to 1.9 K to allow safe operation at fields of up to 8.3 T.

Niobium-titanium superconducting magnet coils (liquid helium cooled) were built to be used in the Alpha Magnetic Spectrometer

Alpha Magnetic Spectrometer

The Alpha Magnetic Spectrometer, also designated AMS-02, is a particle physics experiment module that is mounted on the International Space Station. It is designed to search for various types of unusual matter by measuring cosmic rays. Its experiments will help researchers study the formation of...

 mission to be flown on the international space station

International Space Station

The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...

. They were later replaced by non-superconducting magnets.

The experimental fusion reactor ITER

ITER

ITER is an international nuclear fusion research and engineering project, which is currently building the world's largest and most advanced experimental tokamak nuclear fusion reactor at Cadarache in the south of France...

 uses Niobium-titanium for its poloidal field coils. In 2008 a test coil achieved stable operation at 52 kA and 6.4 Tesla.