Materials / Compare
Aluminum vs. Plastic HDPE
Compare Aluminum vs. Plastic HDPE 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 | 24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min ISO 527 |
| Ultimate tensile strength | 310MPasourcetypical | not sourced |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | not sourced |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 |
| Density | 2,700kg/m³sourcenominal | 950kg/m³sourcetypical, ISO 1183 |
| Strength to weight | 102kN·m/kg4.05x higher | 25.3kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg26.7x higher | 0.947MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) |
| Shear modulus | 25.7GPa81.3x stiffer in shear | 0.316GPa |
| Bulk modulus | 67GPa | 2GPa |
| Speed of sound | 5,030m/s | 973m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) |
| 100 mm part over a 50 °C swing | 118µm growth5.08x less | 600µm growth |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) |
| Heats up and cools (diffusivity) | 69mm²/s332x faster | 0.208mm²/s |
| Thermal shock resistance | 19,159W/m337x more resistant | 56.9W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values |
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 stronger than Plastic HDPE?
Aluminum is stronger: its yield strength is 276 MPa against 24 MPa for Plastic HDPE (11.5x).
Which is lighter, Aluminum or Plastic HDPE?
Plastic HDPE is lighter: 950 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Plastic HDPE?
Aluminum is stiffer: Young's modulus 68.3 GPa against 0.9 GPa for Plastic HDPE, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Plastic HDPE?
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 HDPE |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 26.7x heavier |
| Stiff beam (bending) | lighter | 3.07x heavier |
| Stiff panel or plate | lighter | 49% heavier |
| Strong rod or tie | lighter | 4.05x heavier |
| Strong beam | lighter | 1.79x heavier |
| Strong panel or plate | lighter | 19% 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 HDPE?
Aluminum conducts heat better: 167 W/m·K against 0.445 W/m·K for Plastic HDPE.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 120 µm/m·K for Plastic HDPE.