Materials / Compare
Nickel Inconel 718 vs. Plastic PEEK
Compare Nickel Inconel 718 vs. Plastic PEEK strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 1,207MPasourcetypical, 1.0 in. hot-rolled bar, 0.2% offset | 98MPasourcetypical, tensile yield |
| Ultimate tensile strength | 1,389MPasourcetypical, 1.0 in. bar | not sourced |
| Compressive strength | not sourced | 125MPasourcetypical, 23 C |
| Flexural strength | not sourced | 165MPasourcetypical, flexural stress at yield, 23 C |
| Elongation at break | 20%sourcetypical, 1.0 in. bar | 25%sourcetypical, at break |
| Young's modulus (stiffness) | 200GPasourcetypical, 21 °C, annealed + aged | 4GPasourcetypical (nominal) |
| Density | 8,221kg/m³sourcenominal, annealed and aged | 1,300kg/m³sourcetypical (crystalline) |
| Strength to weight | 147kN·m/kg1.95x higher | 75.4kN·m/kg |
| Stiffness to weight | 24.3MN·m/kg7.91x higher | 3.08MN·m/kg |
| Poisson's ratio | 0.294sourcetypical, 21 °C, annealed + aged | 0.38sourcetypical |
| Shear modulus | 77.3GPa53.3x stiffer in shear | 1.45GPa |
| Bulk modulus | 162GPa | 5.56GPa |
| Speed of sound | 4,932m/s | 1,754m/s |
| Thermal | ||
| Thermal conductivity | 11.4W/m·Ksourcetypical, 21 °C, annealed + aged (calculated from resistivity per footnote a) | 0.29W/m·Ksourcetypical, average, 23 C |
| Thermal expansion | 13.2µm/m·Ksourcetypical, mean 21-93 °C, annealed + aged | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) |
| 100 mm part over a 50 °C swing | 66µm growth4.17x less | 275µm growth |
| Specific heat | 435J/kg·Ksourcetypical, 21 °C | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) |
| Heats up and cools (diffusivity) | 3.19mm²/s31.4x faster | 0.101mm²/s |
| Thermal shock resistance | 3,680W/m45.9x more resistant | 80.1W/m |
| Melting point | 1,260–1,336°Csourcemelting range | 343°Csourcetypical, DSC |
| Glass transition | not sourced | 143°Csourceonset (midpoint 150 C) |
| Max service temperature | 704°Csourceupper use temperature stated by producer | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) |
| Values for | INCONEL alloy 718, standard grade, 1750 °F/1 hr anneal + 1325 °F/8 hr F.C. to 1150 °F aged; Special Metals bulletin SMC-045 typical values | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Nickel Inconel 718 stronger than Plastic PEEK?
Nickel Inconel 718 is stronger: its yield strength is 1,207 MPa against 98 MPa for Plastic PEEK (12.3x).
Which is lighter, Nickel Inconel 718 or Plastic PEEK?
Plastic PEEK is lighter: 1,300 kg/m³ against 8,221 kg/m³ for Nickel Inconel 718.
Which is stiffer, Nickel Inconel 718 or Plastic PEEK?
Nickel Inconel 718 is stiffer: Young's modulus 200 GPa against 4 GPa for Plastic PEEK, so the same part in Nickel Inconel 718 deflects less under the same load.
Which is lighter for the same job, Nickel Inconel 718 or Plastic PEEK?
For the same stiffness or strength: Nickel Inconel 718 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie; Plastic PEEK is lighter for a stiff panel or plate, strong beam, strong panel or plate.
| Part that must be | Nickel Inconel 718 | Plastic PEEK |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 7.91x heavier |
| Stiff beam (bending) | lighter | 12% heavier |
| Stiff panel or plate | 1.72x heavier | lighter |
| Strong rod or tie | lighter | 1.95x heavier |
| Strong beam | 19% heavier | lighter |
| Strong panel or plate | 1.8x heavier | lighter |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Nickel Inconel 718 or Plastic PEEK?
Nickel Inconel 718 conducts heat better: 11.4 W/m·K against 0.29 W/m·K for Plastic PEEK.
Which expands less with temperature?
Nickel Inconel 718 expands less: 13.2 µm/m·K against 55 µm/m·K for Plastic PEEK.