Materials / Compare
Aluminum vs. Glass
Compare Aluminum vs. Glass strength, stiffness, weight and thermal properties.
| Try it on a partA sample part 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 | 41MPasourcetypical mean surface tensile stress at fracture (MOR), 60 s load, weathered, 50% breakage probability |
| Flexural strength | not sourced | 41MPasourcemean MOR (same value as tensile) |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | not sourced |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 72GPasourcetypical |
| Density | 2,700kg/m³sourcenominal | 2,500kg/m³sourcetypical |
| Strength to weight | 102kN·m/kg6.23x higher | 16.4kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg | 28.8MN·m/kg14% higher |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.22sourcetypical |
| Shear modulus | 25.7GPa | 29.5GPa15% stiffer in shear |
| Bulk modulus | 67GPa | 42.9GPa |
| Speed of sound | 5,030m/s | 5,367m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 0.937W/m·Ksourcetypical at 75 F |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 8.3µm/m·Ksourcetypical, 75-575 F |
| 100 mm part over a 50 °C swing | 118µm growth | 41.5µm growth2.84x less |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 880J/kg·Ksourcetypical at 75 F |
| Heats up and cools (diffusivity) | 69mm²/s162x faster | 0.426mm²/s |
| Thermal shock resistance | 19,159W/m382x more resistant | 50.1W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Max service temperature | not sourced | 511°Csourcestrain point (ASTM C336) - stress-relaxation onset, not a rated service limit |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | Annealed soda-lime-silica float glass, Pilkington North America Technical Bulletin ATS-129 (04/2025) |
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 Glass?
Aluminum is stronger: its yield strength is 276 MPa against tensile strength 41 MPa for Glass (6.73x).
Which is lighter, Aluminum or Glass?
Glass is lighter: 2,500 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Glass?
Glass is stiffer: Young's modulus 72 GPa against 68.3 GPa for Aluminum, so the same part in Glass deflects less under the same load.
Which is lighter for the same job, Aluminum or Glass?
For the same stiffness or strength: Aluminum is lighter for a strong rod or tie, strong beam, strong panel or plate; Glass is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate.
| Part that must be | Aluminum | Glass |
|---|---|---|
| Stiff rod or tie (tension) | 14% heavier | lighter |
| Stiff beam (bending) | 11% heavier | lighter |
| Stiff panel or plate | 10% heavier | lighter |
| Strong rod or tie | lighter | 6.23x heavier |
| Strong beam | lighter | 3.3x heavier |
| Strong panel or plate | lighter | 2.4x 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 Glass?
Aluminum conducts heat better: 167 W/m·K against 0.937 W/m·K for Glass.
Which expands less with temperature?
Glass expands less: 8.3 µm/m·K against 23.6 µm/m·K for Aluminum.