Materials / Compare
Plastic PEEK vs. Titanium Ti-6Al-4V
Compare Plastic PEEK vs. Titanium Ti-6Al-4V 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 | 885MPasourcetypical, plate (>0.187 in), annealed, 0.2% offset |
| Ultimate tensile strength | not sourced | 940MPasourcetypical, plate, annealed |
| 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 | 16%sourcetypical, in 2 in., plate annealed |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | 107–122GPasourcetypical range, 20 °C |
| Density | 1,300kg/m³sourcetypical (crystalline) | 4,430kg/m³sourcenominal |
| Strength to weight | 75.4kN·m/kg | 200kN·m/kg2.65x higher |
| Stiffness to weight | 3.08MN·m/kg | 25.8MN·m/kg8.4x higher |
| Poisson's ratio | 0.38sourcetypical | 0.342sourcemean of TIMET measurements |
| Shear modulus | 1.45GPa | 42.7GPa29.4x stiffer in shear |
| Bulk modulus | 5.56GPa | 121GPa |
| Speed of sound | 1,754m/s | 5,084m/s |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 6.6W/m·Ksourcetypical, 20 °C, mill annealed |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | 9µm/m·Ksourcetypical, mean 0-100 °C |
| 100 mm part over a 50 °C swing | 275µm growth | 45µm growth6.11x less |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | 580J/kg·Ksourcetypical, 20 °C |
| Heats up and cools (diffusivity) | 0.101mm²/s | 2.57mm²/s25.3x faster |
| Thermal shock resistance | 80.1W/m | 3,730W/m46.6x more resistant |
| Melting point | 343°Csourcetypical, DSC | 1,630–1,650°Csourcemelting range |
| Glass transition | 143°Csourceonset (midpoint 150 C) | not sourced |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | 400°Csourceupper recommended use temperature |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | TIMETAL 6-4 (Ti-6Al-4V Grade 5) annealed plate typical (TIMET properties manual) + TIMET datasheet TMC-0150 physical properties |
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 Titanium Ti-6Al-4V?
Titanium Ti-6Al-4V is stronger: its yield strength is 885 MPa against 98 MPa for Plastic PEEK (9.03x).
Which is lighter, Plastic PEEK or Titanium Ti-6Al-4V?
Plastic PEEK is lighter: 1,300 kg/m³ against 4,430 kg/m³ for Titanium Ti-6Al-4V.
Which is stiffer, Plastic PEEK or Titanium Ti-6Al-4V?
Titanium Ti-6Al-4V is stiffer: Young's modulus 115 GPa against 4 GPa for Plastic PEEK, so the same part in Titanium Ti-6Al-4V deflects less under the same load.
Which is lighter for the same job, Plastic PEEK or Titanium Ti-6Al-4V?
For the same stiffness or strength: Plastic PEEK is lighter for a stiff panel or plate, strong panel or plate; Titanium Ti-6Al-4V is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie, strong beam.
| Part that must be | Plastic PEEK | Titanium Ti-6Al-4V |
|---|---|---|
| Stiff rod or tie (tension) | 8.4x heavier | lighter |
| Stiff beam (bending) | 1.57x heavier | lighter |
| Stiff panel or plate | lighter | 11% heavier |
| Strong rod or tie | 2.65x heavier | lighter |
| Strong beam | 27% heavier | lighter |
| Strong panel or plate | lighter | 13% 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 Titanium Ti-6Al-4V?
Titanium Ti-6Al-4V conducts heat better: 6.6 W/m·K against 0.29 W/m·K for Plastic PEEK.
Which expands less with temperature?
Titanium Ti-6Al-4V expands less: 9 µm/m·K against 55 µm/m·K for Plastic PEEK.