6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J
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 stronger than Plastic Nylon PA66?
Aluminum is stronger: its yield strength is 276 MPa against 85 MPa for Plastic Nylon PA66 (3.25x).
Which is lighter, Aluminum or Plastic Nylon PA66?
Plastic Nylon PA66 is lighter: 1,130 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Plastic Nylon PA66?
Aluminum is stiffer: Young's modulus 68.3 GPa against 3 GPa for Plastic Nylon PA66, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Plastic Nylon PA66?
For the same stiffness or strength: Aluminum is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie; Plastic Nylon PA66 is lighter for a strong beam, strong panel or plate.
Part that must be
Aluminum
Plastic Nylon PA66
Stiff rod or tie (tension)
lighter
9.53x heavier
Stiff beam (bending)
lighter
2x heavier
Stiff panel or plate
lighter
19% heavier
Strong rod or tie
lighter
36% heavier
Strong beam
9% heavier
lighter
Strong panel or plate
33% 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 or Plastic Nylon PA66?
Aluminum conducts heat better: 167 W/m·K against 0.33 W/m·K for Plastic Nylon PA66.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 98 µm/m·K for Plastic Nylon PA66.