NbTi alloy
Overview
Niobium-titanium alloy superconductor is the “lead material” in superconducting industry. Together with the Nb3Sn superconductor, it is the material of choice for practical superconducting magnet applications, it has a high upper critical magnetic field (about 11T at 4.2K, about 14T at 2K) can be drawn well with copper, has good processing plasticity, high strength, and good superconducting properties
In the existing superconducting technology, niobium-titanium superconducting alloy is the most widely used superconducting material.
The NbTi alloy with a mass ratio of nearly 1:1 has good superconducting electrical properties, and its critical superconducting transition temperature Tc=9.5K can operate at liquid helium temperature, and its transmission current density Jc≥105A/cm2(4.2K) under a 5T(50,000 Gs) magnetic field. The maximum application field is 10T(100,000 Gs)(4.2K).
The alloy also has excellent processing properties, superconducting wire, strip and tube products can be obtained by traditional melting, processing and heat treatment processes.
Classification
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-Ti(40% to 55%).
This alloy component can not only obtain the appropriate high Tc and Hc2, but also can prepare the high current carrying capacity of the superconducting material with a large number of precipitated phases.
There are six grades of niobium titanium alloy superconducting materials used in the world:
Nb-Ti44.0
Nb-Ti46.5 (widely used)
Nb-Ti48.0
Nb-Ti50.0 (widely used)
Nb-Ti53.0
Nb-Ti55.0
Application
The potential demands for Niobium Superconductors in the future are mainly from nuclear fusion reactors, high-speed maglev trains, magnetohydrodynamic (MHD) power plants, and the storage and transmission of underground capacity. There might be more complex superconductors (such as high Te superconductors) coming out in the future to compete with Niobium Superconductors.
Nb-55Ti can be used in anti-corrosion engineering. Nb-55Ti is used for high pressure equipment to filter Gold and Nickel in high pressure and high concentration oxygen environment. Niobium also acts as flame retardant in this environment. Niobium-containing Titanium alloys, such as IMI367, are used in surgical implants, particularly in the production of femoral components for hip repair surgery.
NbTi alloy for quantum technology
Superconductivity plays an important role in the development of quantum technology. Superconducting products such as niobium titanium capillary tube have important applications in quantum communication and quantum computing.
Typical material
| Nb | Ti | H | O | N | C | Fe |
|---|---|---|---|---|---|---|
| Balance | 47.0±1.0 | ≤35ppm | ≤500ppm | ≤100ppm | ≤100ppm | ≤125ppm |
| Ta | Ni | Si | Cu | Al | Cr | |
| ≤1000ppm | ≤50ppm | ≤100ppm | ≤50ppm | ≤50ppm | ≤50ppm |
Mechanical property
| Tensile Rm | 450 | MPa (min) |
|---|---|---|
| Rp 0.2% Yield | 410 | MPa (min) |
| Hardness | 120-170 | HV |
Aging heat treatment
The main purpose of heat treatment is to precipitate α-Ti phase in the metastable β-phase NbTi alloy, which can be used as the magnetic flux pinning center to improve the performance of the superconducting wire. In the process of heat treatment at 375 ~ 420℃, the α-Ti phase precipitates at the intersection of grain boundaries, and then alternates between cold working and heat treatment for several times, and finally forms an effective pinning center.
Available Process
Cold worked and aging heat treated
Product forms
Capillary tube
- ◎ OD 0.50 ~ 3.0 mm
- ◎ WT 0.05 ~ 0.5 mm
Specification of NbTi capillary tube for quantum computer
- ◎ OD1.0mm x WT0.14mm x L1000mm
- ◎ OD1.4mm x WT0.14mm x L1000mm
- ◎ OD2.2mm x WT0.18mm x L1500mm
- ◎ OD2.2mm x WT0.26mm x L1000mm
Precision seamless tube
- ◎ OD 3.0 ~ 100 mm
- ◎ WT 0.10 ~ 10.0 mm
Service
- ◎ Precision cutting
- ◎ Tube surface treatment, like ID surface super mirror polishing, best level could reach Ra0.0015um
- ◎ Tube deep processing, like coiling, bending, end forming, body forming, laser processing, various needles processing, built to drawing and sample, etc.