Materials / Compare
Plastic HDPE vs. Zinc Zamak 3
Compare Plastic HDPE vs. Zinc Zamak 3 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 | 24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min ISO 527 | 221MPasourcetypical |
| Ultimate tensile strength | not sourced | 283MPasourcetypical |
| Elongation at break | not sourced | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 85.5GPasourcetypical |
| Density | 950kg/m³sourcetypical, ISO 1183 | 6,600kg/m³sourcetypical |
| Strength to weight | 25.3kN·m/kg | 33.5kN·m/kg33% higher |
| Stiffness to weight | 0.947MN·m/kg | 13MN·m/kg13.7x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | 0.316GPa | 33.7GPa107x stiffer in shear |
| Bulk modulus | 2GPa | 62GPa |
| Speed of sound | 973m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 113W/m·Ksourcetypical |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 600µm growth | 137µm growth4.38x less |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.208mm²/s | 40.9mm²/s196x faster |
| Thermal shock resistance | 56.9W/m | 7,782W/m137x more resistant |
| Melting point | not sourced | 381–387°Csourcemelting range |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values | Zamak 3 (ASTM B86 die cast), Nathan Trotter (zinc alloy producer) technical data sheet, typical 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 Plastic HDPE stronger than Zinc Zamak 3?
Zinc Zamak 3 is stronger: its yield strength is 221 MPa against 24 MPa for Plastic HDPE (9.21x).
Which is lighter, Plastic HDPE or Zinc Zamak 3?
Plastic HDPE is lighter: 950 kg/m³ against 6,600 kg/m³ for Zinc Zamak 3.
Which is stiffer, Plastic HDPE or Zinc Zamak 3?
Zinc Zamak 3 is stiffer: Young's modulus 85.5 GPa against 0.9 GPa for Plastic HDPE, so the same part in Zinc Zamak 3 deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Zinc Zamak 3?
For the same stiffness or strength: Plastic HDPE is lighter for a stiff panel or plate, strong beam, strong panel or plate; Zinc Zamak 3 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic HDPE | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | 13.7x heavier | lighter |
| Stiff beam (bending) | 40% heavier | lighter |
| Stiff panel or plate | lighter | 1.52x heavier |
| Strong rod or tie | 33% heavier | lighter |
| Strong beam | lighter | 1.58x heavier |
| Strong panel or plate | lighter | 2.29x 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, Plastic HDPE or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 0.445 W/m·K for Plastic HDPE.
Which expands less with temperature?
Zinc Zamak 3 expands less: 27.4 µm/m·K against 120 µm/m·K for Plastic HDPE.