Materials / Compare
Plastic PEEK vs. Zinc Zamak 3
Compare Plastic PEEK 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 | 98MPasourcetypical, tensile yield | 221MPasourcetypical |
| Ultimate tensile strength | not sourced | 283MPasourcetypical |
| Compressive strength | 125MPasourcetypical, 23 C | not sourced |
| Flexural strength | 165MPasourcetypical, flexural stress at yield, 23 C | not sourced |
| Elongation at break | 25%sourcetypical, at break | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | 85.5GPasourcetypical |
| Density | 1,300kg/m³sourcetypical (crystalline) | 6,600kg/m³sourcetypical |
| Strength to weight | 75.4kN·m/kg2.25x higher | 33.5kN·m/kg |
| Stiffness to weight | 3.08MN·m/kg | 13MN·m/kg4.21x higher |
| Poisson's ratio | 0.38sourcetypical | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | 1.45GPa | 33.7GPa23.2x stiffer in shear |
| Bulk modulus | 5.56GPa | 62GPa |
| Speed of sound | 1,754m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 113W/m·Ksourcetypical |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 275µm growth | 137µm growth2.01x less |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.101mm²/s | 40.9mm²/s403x faster |
| Thermal shock resistance | 80.1W/m | 7,782W/m97.2x more resistant |
| Melting point | 343°Csourcetypical, DSC | 381–387°Csourcemelting range |
| Glass transition | 143°Csourceonset (midpoint 150 C) | not sourced |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | not sourced |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | 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 PEEK stronger than Zinc Zamak 3?
Zinc Zamak 3 is stronger: its yield strength is 221 MPa against 98 MPa for Plastic PEEK (2.26x).
Which is lighter, Plastic PEEK or Zinc Zamak 3?
Plastic PEEK is lighter: 1,300 kg/m³ against 6,600 kg/m³ for Zinc Zamak 3.
Which is stiffer, Plastic PEEK or Zinc Zamak 3?
Zinc Zamak 3 is stiffer: Young's modulus 85.5 GPa against 4 GPa for Plastic PEEK, so the same part in Zinc Zamak 3 deflects less under the same load.
Which is lighter for the same job, Plastic PEEK or Zinc Zamak 3?
For the same stiffness or strength: Plastic PEEK is lighter for a stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Zinc Zamak 3 is lighter for a stiff rod or tie (tension).
| Part that must be | Plastic PEEK | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | 4.21x heavier | lighter |
| Stiff beam (bending) | lighter | 10% heavier |
| Stiff panel or plate | lighter | 1.83x heavier |
| Strong rod or tie | lighter | 2.25x heavier |
| Strong beam | lighter | 2.95x heavier |
| Strong panel or plate | lighter | 3.38x 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 PEEK or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 0.29 W/m·K for Plastic PEEK.
Which expands less with temperature?
Zinc Zamak 3 expands less: 27.4 µm/m·K against 55 µm/m·K for Plastic PEEK.