Aluminum A380 vs. Plastic Polycarbonate

Compare Aluminum A380 vs. Plastic Polycarbonate strength, stiffness, weight and thermal properties.

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Plastic PolycarbonateBulk polymer (molded or machined)

Mechanical
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Yield strength	160MPasourcetypical, 25 °C	65MPasourcetypical, tensile yield
Ultimate tensile strength	320MPasourcetypical, 25 °C	65MPasourcetypical, stress at break
Flexural strength	not sourced	97MPasourcetypical, flexural strength
Elongation at break	3.5%sourcetypical	125%sourcetypical, strain at break
Young's modulus (stiffness)	71GPasourcetypical, 25 °C	2.4GPasourcetypical
Density	2,713kg/m³sourcetypical at 68 °F	1,200kg/m³sourcetypical
Strength to weight	59kN·m/kg9% higher	54.2kN·m/kg
Stiffness to weight	26.2MN·m/kg13.1x higher	2MN·m/kg
Poisson's ratio	not sourced	0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1)
Shear modulus	not sourced	0.87GPa
Bulk modulus	not sourced	3.33GPa
Speed of sound	5,116m/s	1,414m/s
Thermal
Thermal conductivity	96.2W/m·Ksourcetypical at 68 °F	0.2W/m·Ksourcetypical, through-plane, 23 C
Thermal expansion	21.8µm/m·Ksourcetypical, 68-572 °F (20-300 °C)	65µm/m·Ksourcetypical, 23-55 C, parallel and normal
100 mm part over a 50 °C swing	109µm growth2.98x less	325µm growth
Specific heat	963J/kg·Ksourcetypical at 68 °F	1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766
Heats up and cools (diffusivity)	36.8mm²/s259x faster	0.142mm²/s
Thermal shock resistance	not sourced	51.7W/m
Glass transition	not sourced	144°Csourcetypical, DSC 10 C/min
Max service temperature	not sourced	125°CsourceUL 746B RTI, tensile strength, 1.5 mm
Values for	A380 aluminium high-pressure die-casting alloy, typical properties; Rheocast Company (aluminium die caster, Germantown WI) A380 alloy data page.	Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, 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 Aluminum A380 stronger than Plastic Polycarbonate?

Aluminum A380 is stronger: its yield strength is 160 MPa against 65 MPa for Plastic Polycarbonate (2.46x).

Which is lighter, Aluminum A380 or Plastic Polycarbonate?

Plastic Polycarbonate is lighter: 1,200 kg/m³ against 2,713 kg/m³ for Aluminum A380.

Which is stiffer, Aluminum A380 or Plastic Polycarbonate?

Aluminum A380 is stiffer: Young's modulus 71 GPa against 2.4 GPa for Plastic Polycarbonate, so the same part in Aluminum A380 deflects less under the same load.

Which is lighter for the same job, Aluminum A380 or Plastic Polycarbonate?

For the same stiffness or strength: Aluminum A380 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie; Plastic Polycarbonate is lighter for a strong beam, strong panel or plate.

Part that must be	Aluminum A380	Plastic Polycarbonate
Stiff rod or tie (tension)	lighter	13.1x heavier
Stiff beam (bending)	lighter	2.41x heavier
Stiff panel or plate	lighter	37% heavier
Strong rod or tie	lighter	9% heavier
Strong beam	24% heavier	lighter
Strong panel or plate	44% heavier	lighter

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 A380 or Plastic Polycarbonate?

Aluminum A380 conducts heat better: 96.2 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.

Which expands less with temperature?

Aluminum A380 expands less: 21.8 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.

Among 72 materials

Stiffness against density

Strength against density