Materials / Compare
Aluminum 6061-T6 vs. Plastic PEEK
Compare Aluminum 6061-T6 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 | 276MPasourcetypical, 0.2% offset, .500 in dia specimen | 98MPasourcetypical, tensile yield |
| Ultimate tensile strength | 310MPasourcetypical | not sourced |
| Compressive strength | not sourced | 125MPasourcetypical, 23 C |
| Flexural strength | not sourced | 165MPasourcetypical, flexural stress at yield, 23 C |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | 25%sourcetypical, at break |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 4GPasourcetypical (nominal) |
| Density | 2,700kg/m³sourcenominal | 1,300kg/m³sourcetypical (crystalline) |
| Strength to weight | 102kN·m/kg36% higher | 75.4kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg8.22x higher | 3.08MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.38sourcetypical |
| Shear modulus | 25.7GPa17.7x stiffer in shear | 1.45GPa |
| Bulk modulus | 67GPa | 5.56GPa |
| Speed of sound | 5,030m/s | 1,754m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.29W/m·Ksourcetypical, average, 23 C |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) |
| 100 mm part over a 50 °C swing | 118µm growth2.33x less | 275µm growth |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) |
| Heats up and cools (diffusivity) | 69mm²/s681x faster | 0.101mm²/s |
| Thermal shock resistance | 19,159W/m239x more resistant | 80.1W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | 343°Csourcetypical, DSC |
| Glass transition | not sourced | 143°Csourceonset (midpoint 150 C) |
| Max service temperature | not sourced | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties; Poisson from MIL-HDBK-5J | 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 Aluminum 6061-T6 stronger than Plastic PEEK?
Aluminum 6061-T6 is stronger: its yield strength is 276 MPa against 98 MPa for Plastic PEEK (2.82x).
Which is lighter, Aluminum 6061-T6 or Plastic PEEK?
Plastic PEEK is lighter: 1,300 kg/m³ against 2,700 kg/m³ for Aluminum 6061-T6.
Which is stiffer, Aluminum 6061-T6 or Plastic PEEK?
Aluminum 6061-T6 is stiffer: Young's modulus 68.3 GPa against 4 GPa for Plastic PEEK, so the same part in Aluminum 6061-T6 deflects less under the same load.
Which is lighter for the same job, Aluminum 6061-T6 or Plastic PEEK?
For the same stiffness or strength: Aluminum 6061-T6 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie; Plastic PEEK is lighter for a strong beam, strong panel or plate.
| Part that must be | Aluminum 6061-T6 | Plastic PEEK |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 8.22x heavier |
| Stiff beam (bending) | lighter | 1.99x heavier |
| Stiff panel or plate | lighter | 24% heavier |
| Strong rod or tie | lighter | 36% heavier |
| Strong beam | 4% heavier | lighter |
| Strong panel or plate | 24% 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, Aluminum 6061-T6 or Plastic PEEK?
Aluminum 6061-T6 conducts heat better: 167 W/m·K against 0.29 W/m·K for Plastic PEEK.
Which expands less with temperature?
Aluminum 6061-T6 expands less: 23.6 µm/m·K against 55 µm/m·K for Plastic PEEK.