Materials / Compare
Aluminum vs. Plastic PETG
Compare Aluminum vs. Plastic PETG 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 | 46.2MPasourcetypical |
| Ultimate tensile strength | 310MPasourcetypical | 46.2MPasourcetypical, peak stress (= stress at yield) |
| Flexural strength | not sourced | 78.9MPasourcetypical |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | 7.6%sourcetypical |
| Young's modulus (stiffness) | 68.3GPasourcetypical35.2x stiffer | 1.94GPasourcetypical |
| Density | 2,700kg/m³sourcenominal | 1,270kg/m³sourcetypical |
| Strength to weight | 102kN·m/kg2.81x higher | 36.4kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg16.6x higher | 1.53MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | not sourced |
| Shear modulus | 25.7GPa | not sourced |
| Bulk modulus | 67GPa | not sourced |
| Speed of sound | 5,030m/s | 1,236m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical |
| 100 mm part over a 50 °C swing | 118µm growth2.16x less | 255µm growth |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed) |
| Heats up and cools (diffusivity) | 69mm²/s543x faster | 0.127mm²/s |
| Thermal shock resistance | 19,159W/m | not sourced |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Glass transition | not sourced | 77.4°Csourcetypical |
| Max service temperature | not sourced | 76.2°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | Ultimaker PETG, 3D-printed specimens, XY (flat); Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS v1.00, April 29, 2022. |
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.
Plastic PETG is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Aluminum stronger than Plastic PETG?
Aluminum is stronger: its yield strength is 276 MPa against 46.2 MPa for Plastic PETG (5.97x).
Which is lighter, Aluminum or Plastic PETG?
Plastic PETG is lighter: 1,270 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Plastic PETG?
Aluminum is stiffer: Young's modulus 68.3 GPa against 1.94 GPa for Plastic PETG, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Plastic PETG?
For the same stiffness or strength: Aluminum is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Aluminum | Plastic PETG |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 16.6x heavier |
| Stiff beam (bending) | lighter | 2.79x heavier |
| Stiff panel or plate | lighter | 1.54x heavier |
| Strong rod or tie | lighter | 2.81x heavier |
| Strong beam | lighter | 1.55x heavier |
| Strong panel or plate | lighter | 15% heavier |
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 or Plastic PETG?
Aluminum conducts heat better: 167 W/m·K against 0.21 W/m·K for Plastic PETG.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 51 µm/m·K for Plastic PETG.