Plastic Polycarbonate vs. Titanium Ti-6Al-4V

Compare Plastic Polycarbonate vs. Titanium Ti-6Al-4V strength, stiffness, weight and thermal properties.

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Plastic PolycarbonateBulk polymer (molded or machined)

Mechanical
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Yield strength	65MPasourcetypical, tensile yield	885MPasourcetypical, plate (>0.187 in), annealed, 0.2% offset
Ultimate tensile strength	65MPasourcetypical, stress at break	940MPasourcetypical, plate, annealed
Flexural strength	97MPasourcetypical, flexural strength	not sourced
Elongation at break	125%sourcetypical, strain at break	16%sourcetypical, in 2 in., plate annealed
Young's modulus (stiffness)	2.4GPasourcetypical	107–122GPasourcetypical range, 20 °C
Density	1,200kg/m³sourcetypical	4,430kg/m³sourcenominal
Strength to weight	54.2kN·m/kg	200kN·m/kg3.69x higher
Stiffness to weight	2MN·m/kg	25.8MN·m/kg12.9x higher
Poisson's ratio	0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1)	0.342sourcemean of TIMET measurements
Shear modulus	0.87GPa	42.7GPa49.1x stiffer in shear
Bulk modulus	3.33GPa	121GPa
Speed of sound	1,414m/s	5,084m/s
Thermal
Thermal conductivity	0.2W/m·Ksourcetypical, through-plane, 23 C	6.6W/m·Ksourcetypical, 20 °C, mill annealed
Thermal expansion	65µm/m·Ksourcetypical, 23-55 C, parallel and normal	9µm/m·Ksourcetypical, mean 0-100 °C
100 mm part over a 50 °C swing	325µm growth	45µm growth7.22x less
Specific heat	1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766	580J/kg·Ksourcetypical, 20 °C
Heats up and cools (diffusivity)	0.142mm²/s	2.57mm²/s18.1x faster
Thermal shock resistance	51.7W/m	3,730W/m72.2x more resistant
Melting point	not sourced	1,630–1,650°Csourcemelting range
Glass transition	144°Csourcetypical, DSC 10 C/min	not sourced
Max service temperature	125°CsourceUL 746B RTI, tensile strength, 1.5 mm	400°Csourceupper recommended use temperature
Values for	Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values	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 Polycarbonate stronger than Titanium Ti-6Al-4V?

Titanium Ti-6Al-4V is stronger: its yield strength is 885 MPa against 65 MPa for Plastic Polycarbonate (13.6x).

Which is lighter, Plastic Polycarbonate or Titanium Ti-6Al-4V?

Plastic Polycarbonate is lighter: 1,200 kg/m³ against 4,430 kg/m³ for Titanium Ti-6Al-4V.

Which is stiffer, Plastic Polycarbonate or Titanium Ti-6Al-4V?

Titanium Ti-6Al-4V is stiffer: Young's modulus 115 GPa against 2.4 GPa for Plastic Polycarbonate, so the same part in Titanium Ti-6Al-4V deflects less under the same load.

Which is lighter for the same job, Plastic Polycarbonate or Titanium Ti-6Al-4V?

For the same stiffness or strength: Plastic Polycarbonate is lighter for a stiff 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 Polycarbonate	Titanium Ti-6Al-4V
Stiff rod or tie (tension)	12.9x heavier	lighter
Stiff beam (bending)	1.87x heavier	lighter
Stiff panel or plate	lighter	2% heavier
Strong rod or tie	3.69x heavier	lighter
Strong beam	1.54x heavier	lighter
Strong panel or plate	about equal	about equal

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 Polycarbonate or Titanium Ti-6Al-4V?

Titanium Ti-6Al-4V conducts heat better: 6.6 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.

Which expands less with temperature?

Titanium Ti-6Al-4V expands less: 9 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.

Among 59 materials

Stiffness against density

Strength against density