Materials / Compare
Aluminum vs. Plastic Polypropylene
Compare Aluminum vs. Plastic Polypropylene 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 | 33MPasourcetypical, tensile stress at yield 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 | 1.45GPasourcetypical, tensile modulus ISO 527 |
| Density | 2,700kg/m³sourcenominal | 900kg/m³sourcetypical, 23 °C ISO 1183-1 |
| Strength to weight | 102kN·m/kg2.79x higher | 36.7kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg15.7x higher | 1.61MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.42sourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) |
| Shear modulus | 25.7GPa50.3x stiffer in shear | 0.511GPa |
| Bulk modulus | 67GPa | 3.02GPa |
| Speed of sound | 5,030m/s | 1,269m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) |
| 100 mm part over a 50 °C swing | 118µm growth3.81x less | 450µm growth |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | not sourced |
| Heats up and cools (diffusivity) | 69mm²/s | not sourced |
| Thermal shock resistance | 19,159W/m670x more resistant | 28.6W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Max service temperature | not sourced | 90°CsourceHDT 0.45 MPa (ISO 75B), unannealed |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), 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 Polypropylene?
Aluminum is stronger: its yield strength is 276 MPa against 33 MPa for Plastic Polypropylene (8.36x).
Which is lighter, Aluminum or Plastic Polypropylene?
Plastic Polypropylene is lighter: 900 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Plastic Polypropylene?
Aluminum is stiffer: Young's modulus 68.3 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Plastic Polypropylene?
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; Plastic Polypropylene is lighter for a strong panel or plate.
| Part that must be | Aluminum | Plastic Polypropylene |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 15.7x heavier |
| Stiff beam (bending) | lighter | 2.29x heavier |
| Stiff panel or plate | lighter | 20% heavier |
| Strong rod or tie | lighter | 2.79x heavier |
| Strong beam | lighter | 37% heavier |
| Strong panel or plate | 4% 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 or Plastic Polypropylene?
Aluminum conducts heat better: 167 W/m·K against 0.195 W/m·K for Plastic Polypropylene.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 90 µm/m·K for Plastic Polypropylene.