Aluminum A380 vs. Plastic Nylon PA66

Compare Aluminum A380 vs. Plastic Nylon PA66 strength, stiffness, weight and thermal properties.

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Plastic Nylon PA66Bulk polymer (molded or machined)

Mechanical
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Yield strength	160MPasourcetypical, 25 °C	85MPasourcetypical, dry
Ultimate tensile strength	320MPasourcetypical, 25 °C	not sourced
Elongation at break	3.5%sourcetypical	30%sourcenominal strain at break, dry
Young's modulus (stiffness)	71GPasourcetypical, 25 °C	3GPasourcetypical, dry
Density	2,713kg/m³sourcetypical at 68 °F	1,130kg/m³sourcetypical
Strength to weight	59kN·m/kg	75.2kN·m/kg28% higher
Stiffness to weight	26.2MN·m/kg9.86x higher	2.65MN·m/kg
Poisson's ratio	not sourced	0.4sourcebase material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro Table 3-1)
Shear modulus	not sourced	1.07GPa
Bulk modulus	not sourced	5GPa
Speed of sound	5,116m/s	1,629m/s
Thermal
Thermal conductivity	96.2W/m·Ksourcetypical at 68 °F	0.33W/m·Ksourcetypical
Thermal expansion	21.8µm/m·Ksourcetypical, 68-572 °F (20-300 °C)	98µm/m·Ksourcelongitudinal, 23-55 °C
100 mm part over a 50 °C swing	109µm growth4.5x less	490µm growth
Specific heat	963J/kg·Ksourcetypical at 68 °F	1,700J/kg·Ksourcetypical
Heats up and cools (diffusivity)	36.8mm²/s214x faster	0.172mm²/s
Thermal shock resistance	not sourced	57.2W/m
Melting point	not sourced	260°CsourceDSC
Max service temperature	not sourced	101°CsourceIEC 60216 temperature index, 20000 h
Values for	A380 aluminium high-pressure die-casting alloy, typical properties; Rheocast Company (aluminium die caster, Germantown WI) A380 alloy data page.	BASF Ultramid A3K (PA66, unreinforced injection-moulding grade), Product Information 02/2026, dry values (ISO methods)

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 Nylon PA66?

Aluminum A380 is stronger: its yield strength is 160 MPa against 85 MPa for Plastic Nylon PA66 (1.88x).

Which is lighter, Aluminum A380 or Plastic Nylon PA66?

Plastic Nylon PA66 is lighter: 1,130 kg/m³ against 2,713 kg/m³ for Aluminum A380.

Which is stiffer, Aluminum A380 or Plastic Nylon PA66?

Aluminum A380 is stiffer: Young's modulus 71 GPa against 3 GPa for Plastic Nylon PA66, so the same part in Aluminum A380 deflects less under the same load.

Which is lighter for the same job, Aluminum A380 or Plastic Nylon PA66?

For the same stiffness or strength: Aluminum A380 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic Nylon PA66 is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum A380	Plastic Nylon PA66
Stiff rod or tie (tension)	lighter	9.86x heavier
Stiff beam (bending)	lighter	2.03x heavier
Stiff panel or plate	lighter	20% heavier
Strong rod or tie	28% heavier	lighter
Strong beam	1.57x heavier	lighter
Strong panel or plate	1.75x 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 Nylon PA66?

Aluminum A380 conducts heat better: 96.2 W/m·K against 0.33 W/m·K for Plastic Nylon PA66.

Which expands less with temperature?

Aluminum A380 expands less: 21.8 µm/m·K against 98 µm/m·K for Plastic Nylon PA66.

Among 72 materials

Stiffness against density

Strength against density