Refractory Metal NbTi
NbTi is a ductile niobium–titanium alloy and the workhorse Type-II superconductor, drawn into fine multifilamentary wire in a copper matrix for magnet windings.
Reference datasheet — NbTi is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
NbTi tempers and conditions
NbTi is supplied in 4 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for NbTi billets, extrusion feedstock, rod and sheet; maximum ductility for subsequent co-extrusion and drawing. | 350 | 620 | 25 | 160 HB | 12 W/m·K |
Hot worked (extruded / forged) bar, as-worked | Choose for as-forged or as-extruded NbTi bar and monofilament preform stock where partial work hardening is acceptable. | 520 | 720 | 18 | 12 HRC | 2.9 % IACS |
Cold worked | Bare NbTi filament or fine wire after heavy drawing reduction, before or between precipitation heat treatments; highest strength, low ductility. | 900 | 1,000 | 4 | 28 HRC | 2.7 % IACS |
Cold drawn with intermediate α-Ti precipitation heat treatments | The functional condition of finished superconducting filaments: 3–5 heat treatments near 400 °C interleaved with drawing to create α-Ti flux-pinning ribbons and maximum Jc. | 930 | 1,050 | 5 | 26 HRC | 2.7 % IACS |
Supply forms, finishes and certifications
Ways NbTi is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Cu/NbTi | Copper-stabilized multifilamentary composite wire | Supply option |
What is NbTi?
NbTi is a ductile niobium–titanium alloy and the workhorse Type-II superconductor, drawn into fine multifilamentary wire in a copper matrix for magnet windings. Annealed material shows 350 MPa yield, 620 MPa tensile, 25 % elongation, 160 HB (88 HRB) and 12 W/m·K thermal conductivity, with a formability score of 92 that supports extreme cold-drawing reductions. Practical limits are a 400 °C maximum service temperature, gummy machining behaviour (score 20) and loss of superconducting performance near welds from O/N/H pickup. It is supplied mainly as Cu/NbTi composite wire and cable rather than plate. NbTi has a density of 6.05 g/cm³ (0.219 lb/in³), lighter than 87% of refractory metal grades. It melts at 1,900°C (3,452 °F). NbTi has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of refractory metal grades. Elongation at break is 25% and the elastic modulus is 65 GPa (9.43 Msi).
What is NbTi used for?
- MRI magnet wire
- particle accelerator superconducting coils
- fusion reactor magnets (e.g. ITER)
- superconducting cables
Advantages
- Forms and bends easily — 92/100, better than 95% of refractory metal grades
- Lightweight — 6.05 g/cm³ (0.219 lb/in³), better than 87% of refractory metal grades
Limitations
- Low stiffness — 65 GPa (9.43 Msi), worse than 100% of refractory metal grades
- Poor heat conductor — 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 98% of refractory metal grades
- Low electrical conductivity — 2.9 % IACS, worse than 83% of refractory metal grades
- Difficult to machine — 20/100, worse than 77% of refractory metal grades
NbTi properties
Typical room-temperature values for NbTi-ANN; bars are the position among refractory metal grades.
Physical3
NbTi has a density of 6.05 g/cm³ (0.219 lb/in³), lighter than 87% of refractory metal grades. It melts at 1,900°C (3,452 °F).
Mechanical10
NbTi has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of refractory metal grades. Elongation at break is 25% and the elastic modulus is 65 GPa (9.43 Msi).
Thermal6
NbTi is rated for continuous service to 400°C (752 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 98% of refractory metal grades. Thermal expansion is 8 µm/m·K (4.44 µin/in·°F).
Electrical3
NbTi conducts electricity at 2.9 % IACS, worse than 83% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 52% of refractory metal grades.
Sustainability3
Producing a kilogram of NbTi takes about 700 MJ of energy and emits 45 kg of CO₂ — less than 65% of refractory metal grades. Typical recycled content is 10%.
Manufacturability8
NbTi's machinability is poor (20/100, worse than 77% of refractory metal grades); weldability fair (45/100); formability excellent (92/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. NbTi is highlighted; hover a dot for its name, or open the interactive family chart.
Working with NbTi
Is NbTi easy to machine?
Machines like commercially pure titanium — gummy and work-hardening; use sharp uncoated carbide, low speed (15–30 m/min), heavy positive rake, flood coolant and never dwell.
Can NbTi be welded?
Weld only by EB or GTAW in high-purity argon/vacuum chambers; O/N/H pickup above ~300 °C causes embrittlement and destroys superconducting performance near the joint.
Can NbTi be formed, bent or molded?
Outstandingly cold-drawable — area reductions of 10^5 with intermediate 400 °C precipitation treatments; co-extrude in a copper can at 600–700 °C, avoid intermetallic-forming barriers (use Nb diffusion barrier with Cu).
NbTi chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| TiNb-47Ti nominal; Nb-46.5Ti and Nb-50Ti also produced | 46.5 – 48 | 47 |
| Tatypical superconductor-grade limit | ≤ 0.1 | |
| Fe | ≤ 0.03 | |
| Ointerstitials controlled to preserve drawability | ≤ 0.06 | |
| C | ≤ 0.02 | |
| N | ≤ 0.01 | |
| H | ≤ 0 | |
| Nb | balance |
What surface finishes work on NbTi?
Chemically etch/pickle in HNO3-HF, then anodize for coloured insulating oxide; copper cladding is normally left bright or given a thin Sn/Ag or Formvar/polyimide insulation.
Equivalent designations
Standards and trade names that resolve to Refractory Metal NbTi in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Nb-47Ti
How much does NbTi cost?
NbTi is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
NbTi — frequently asked
What is NbTi used for?
NbTi is typically used for MRI magnet wire, particle accelerator superconducting coils, fusion reactor magnets (e.g. ITER) and superconducting cables. In short: standard NbTi superconductor wire; formability score 92; cold-drawn, not welded.
What is the yield strength of NbTi?
NbTi has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 57% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is NbTi easy to machine?
Not especially — machinability is rated poor (20/100, worse than 77% of refractory metal grades). Machines like commercially pure titanium — gummy and work-hardening; use sharp uncoated carbide, low speed (15–30 m/min), heavy positive rake, flood coolant and never dwell.
Can NbTi be welded?
With care — weldability is rated fair (45/100). Weld only by EB or GTAW in high-purity argon/vacuum chambers; O/N/H pickup above ~300 °C causes embrittlement and destroys superconducting performance near the joint.
What surface finishes work on NbTi?
Chemically etch/pickle in HNO3-HF, then anodize for coloured insulating oxide; copper cladding is normally left bright or given a thin Sn/Ag or Formvar/polyimide insulation.
Can NbTi be formed, bent or molded?
Outstandingly cold-drawable — area reductions of 10^5 with intermediate 400 °C precipitation treatments; co-extrude in a copper can at 600–700 °C, avoid intermetallic-forming barriers (use Nb diffusion barrier with Cu).
What is the maximum service temperature of NbTi?
NbTi is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between NbTi-ANN and NbTi-CW?
ANN is the default condition — standard stocked condition for NbTi billets, extrusion feedstock, rod and sheet; maximum ductility for subsequent co-extrusion and drawing. CW: bare NbTi filament or fine wire after heavy drawing reduction, before or between precipitation heat treatments; highest strength, low ductility. Yield strength is 350 MPa in ANN versus 900 MPa in CW.
How much does NbTi cost?
NbTi is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Handbook of Superconducting Materials (Cardwell & Ginley) — IOP Publishing (2003)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- NIST Cryogenic Material Properties Database — NIST (2020)
- NbTi superconducting wire and NbTi alloy rod datasheets — Supercon Inc. / Luvata / Bruker EAS / WST (2023)
- IEC 61788 series — Superconductivity: critical current and mechanical test methods — IEC (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.