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Nickel Alloy Inconel 625 vs Nitinol

Nickel Alloy · grade comparison

Nickel Alloy Inconel 625 and Nitinol are both nickel alloy grades. Inconel 625 is the stronger of the two: yield strength 490 MPa (71.1 ksi) against 400 MPa (58 ksi) for Nitinol, about 23% more. Inconel 625 is the more ductile: elongation 45% versus 30% for Nitinol, and Nitinol is harder (250 HV vs 200 HV). Nitinol is lighter (6.45 g/cm³ vs 8.44 g/cm³ for Inconel 625) and Inconel 625 is stiffer (207.5 GPa vs 75 GPa). On the shop floor, Inconel 625 welds better (excellent vs fair).

Inconel 625Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

NitinolChoose it when weight is the constraint.

Inconel 625 vs Nitinol: properties

Inconel 625Nitinol

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207.5 GPa30.1 Msi
75 GPa10.9 Msi

Shear Modulus

79 GPa11.5 Msi
24 GPa3.5 Msi

Bulk Modulus

155 GPa22.5 Msi
—

Poisson's Ratio

0.28
0.33

Tensile Strength (Ultimate)

930 MPa135 ksi
950 MPa138 ksi

Yield Strength (0.2% offset)

490 MPa71.1 ksi
400 MPa58 ksi

Elongation at Break

45%
30%

Reduction in Area

55%
—

Compressive Strength

500 MPa72.5 ksi
1,000 MPa145 ksi

Shear Strength

600 MPa87 ksi
—

Fatigue Strength (Endurance Limit)

420 MPa60.9 ksi
350 MPa50.8 ksi

Fracture Toughness (K_IC)

110 MPa·√m100 ksi·√in
40 MPa·√m36.4 ksi·√in

Charpy V-Notch Impact (RT)

120 J88.5 ft·lbf
—

Hardness, Brinell

190 HB
—

Hardness, Rockwell B

92 HRB
—

Hardness, Vickers

200 HV
250 HV

Hardness, Rockwell C

—
22 HRC

Physical

Density and transition temperatures.

Density

8.44 g/cm³0.3 lb/in³
6.45 g/cm³0.23 lb/in³

Melting Point (Solidus)

1,290°C2,354 °F
1,300°C2,372 °F

Liquidus Temperature

1,350°C2,462 °F
1,310°C2,390 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

9.8 W/m·K5.7 BTU/hr·ft·°F
18 W/m·K10.4 BTU/hr·ft·°F

Specific Heat Capacity

410 J/kg·K0.1 BTU/lb·°F
500 J/kg·K0.12 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.8 µm/m·K7.1 µin/in·°F
11 µm/m·K6.1 µin/in·°F

Latent Heat of Fusion

290 J/g125 BTU/lb
—

Max Service Temperature (continuous)

650°C1,202 °F
300°C572 °F

Min Service Temperature

-253°C-423 °F
-196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.3 % IACS
1.7 % IACS

Electrical Resistivity

1.29×10⁻⁶ Ω·m50.8 µΩ·in
1×10⁻⁶ Ω·m39.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.1 V
-0.25 V

Corrosion Resistance

90 / 100
82 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

18 / 100
12 / 100

Machinability Rating (AISI 1212 = 100 %)

12%
10%

Weldability

88 / 100
35 / 100

Formability (cold)

70 / 100
45 / 100

Castability

45 / 100
15 / 100

Brazeability / Solderability

65 / 100
20 / 100

Polishability

72 / 100
70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

225 MJ/kg96,733 BTU/lb
400 MJ/kg171,969 BTU/lb

Embodied Carbon (primary production)

14 kg CO₂/kg
26 kg CO₂/kg

Embodied Water

300 L/kg35.9 gal/lb
900 L/kg108 gal/lb

Typical Recycled Content

35%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

110 kN·m/kg
147 kN·m/kg

Specific Stiffness (E / density)

24.6 MN·m/kg
11.6 MN·m/kg

Modulus of Resilience

579 kJ/m³
1,067 kJ/m³

Thermal Diffusivity

2.8 mm²/s
5.6 mm²/s

Thermal Shock Resistance Index

3
21

Strength versus weight

Yield strength against density for every nickel alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0006.577.588.59Density (g/cm³)Yield strength (MPa) — log scaleNitinolInconel 625

Manufacturing and finishing

CapabilityInconel 625Nitinol
3D printingYes—
Default conditionOO
Relative cost$$$ Premium$$$ Premium
Min. machined wall1.5 mm1.5 mm
Best machined surfaceRa 1.6 µmRa 1.6 µm

Both are offered for CNC machining and Sheet metal. Both take the same 5 finishes: Electropolishing, Gold Plating, HVOF Coating, Plasma Spray, Silver Plating.

Inconel 625 vs Nitinol — frequently asked

Is Inconel 625 stronger than Nitinol?

Yes. Inconel 625 has a typical yield strength of 490 MPa (71.1 ksi) against 400 MPa (58 ksi) for Nitinol — about 23% more. Tensile strength is 930 MPa (135 ksi) vs 950 MPa (138 ksi).

Which is cheaper, Inconel 625 or Nitinol?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, Inconel 625 or Nitinol?

Inconel 625. Its machinability rates poor (18/100) against not recommended (12/100) for Nitinol; for welding the order is Inconel 625 first (excellent, 88/100) then Nitinol (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Inconel 625 and Nitinol side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.