Materials / Compare
Aluminum vs. Plastic PMMA
Compare Aluminum vs. Plastic PMMA 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 | not given (tensile used) |
| Ultimate tensile strength | 310MPasourcetypical | 80MPasourcetypical, 23 °C |
| Compressive strength | not sourced | 110MPasourcecompressive yield stress, typical |
| Flexural strength | not sourced | 115MPasourcetypical |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | 5.5%sourcetypical |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 3.3GPasourcetypical, short-term |
| Density | 2,700kg/m³sourcenominal | 1,190kg/m³sourcetypical |
| Strength to weight | 102kN·m/kg1.52x higher | 67.2kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg9.12x higher | 2.77MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.37sourcetypical |
| Shear modulus | 25.7GPa21.3x stiffer in shear | 1.2GPa |
| Bulk modulus | 67GPa | 4.23GPa |
| Speed of sound | 5,030m/s | 1,665m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.19W/m·Ksourcetypical |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 70µm/m·Ksource0-50 °C |
| 100 mm part over a 50 °C swing | 118µm growth2.97x less | 350µm growth |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 1,470J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 69mm²/s636x faster | 0.109mm²/s |
| Thermal shock resistance | 19,159W/m462x more resistant | 41.5W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Max service temperature | not sourced | 80°Csourcemax. permanent service temperature |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1) |
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 PMMA?
Aluminum is stronger: its yield strength is 276 MPa against tensile strength 80 MPa for Plastic PMMA (3.45x).
Which is lighter, Aluminum or Plastic PMMA?
Plastic PMMA is lighter: 1,190 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Plastic PMMA?
Aluminum is stiffer: Young's modulus 68.3 GPa against 3.3 GPa for Plastic PMMA, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Plastic PMMA?
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; Plastic PMMA is lighter for a strong panel or plate.
| Part that must be | Aluminum | Plastic PMMA |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 9.12x heavier |
| Stiff beam (bending) | lighter | 2.01x heavier |
| Stiff panel or plate | lighter | 21% heavier |
| Strong rod or tie | lighter | 1.52x heavier |
| Strong beam | about equal | about equal |
| Strong panel or plate | 22% 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 PMMA?
Aluminum conducts heat better: 167 W/m·K against 0.19 W/m·K for Plastic PMMA.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 70 µm/m·K for Plastic PMMA.