Plastic ABS (bulk/injection) vs. Aluminum 2024-T351

Compare Plastic ABS (bulk/injection) vs. Aluminum 2024-T351 strength, stiffness, weight and thermal properties.

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Plastic ABS (bulk/injection)Bulk polymer (molded or machined)

Aluminum 2024-T351Wrought

Mechanical
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Yield strength	45MPasourcetypical, tensile stress at yield 23 °C	324MPasourcetypical, 0.2% offset, .500 in dia specimen
Ultimate tensile strength	not sourced	469MPasourcetypical
Flexural strength	65MPasourcetypical, 23 °C	not sourced
Elongation at break	10%sourcenominal strain at break, 23 °C	19%sourcetypical, in 4D
Young's modulus (stiffness)	2.3GPasourcetypical	73.1GPasourcetypical31.8x stiffer
Density	1,040kg/m³sourcetypical	2,770kg/m³sourcenominal
Strength to weight	43.3kN·m/kg	117kN·m/kg2.7x higher
Stiffness to weight	2.21MN·m/kg	26.4MN·m/kg11.9x higher
Poisson's ratio	0.39sourcetypical, ABS family (Covestro Part and Mold Design guide, Table 3-1)	0.33sourcetypical (handbook physical constant), all tempers
Shear modulus	0.827GPa	27.5GPa33.2x stiffer in shear
Bulk modulus	3.48GPa	71.7GPa
Speed of sound	1,487m/s	5,137m/s
Thermal
Thermal conductivity	0.17W/m·Ksourcetypical	120W/m·Ksourcetypical, 20 °C
Thermal expansion	80–110µm/m·Ksourcerange	22.9µm/m·Ksourcetypical, mean 20-100 °C
100 mm part over a 50 °C swing	475µm growth	115µm growth4.15x less
Specific heat	not sourced	875J/kg·Ksourcetypical, at 100 °C
Heats up and cools (diffusivity)	not sourced	49.5mm²/s
Thermal shock resistance	21.4W/m	15,561W/m729x more resistant
Melting point	not sourced	502–638°Csourcemelting range
Max service temperature	94°CsourceHDT 1.8 MPa (annealed 4 h/80 °C)	not sourced
Values for	INEOS Styrolution Terluran GP-22 general-purpose injection-molding ABS, ISO typical values (TDS revision 08/01/2022)	2024-T4/T351, Kaiser Aluminum sheet, coil & plate typical datasheet; Poisson from MIL-HDBK-5J

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 ABS (bulk/injection) stronger than Aluminum 2024-T351?

Aluminum 2024-T351 is stronger: its yield strength is 324 MPa against 45 MPa for Plastic ABS (bulk/injection) (7.2x).

Which is lighter, Plastic ABS (bulk/injection) or Aluminum 2024-T351?

Plastic ABS (bulk/injection) is lighter: 1,040 kg/m³ against 2,770 kg/m³ for Aluminum 2024-T351.

Which is stiffer, Plastic ABS (bulk/injection) or Aluminum 2024-T351?

Aluminum 2024-T351 is stiffer: Young's modulus 73.1 GPa against 2.3 GPa for Plastic ABS (bulk/injection), so the same part in Aluminum 2024-T351 deflects less under the same load.

Which is lighter for the same job, Plastic ABS (bulk/injection) or Aluminum 2024-T351?

For the same stiffness or strength: Aluminum 2024-T351 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam.

Part that must be	Plastic ABS (bulk/injection)	Aluminum 2024-T351
Stiff rod or tie (tension)	11.9x heavier	lighter
Stiff beam (bending)	2.12x heavier	lighter
Stiff panel or plate	19% heavier	lighter
Strong rod or tie	2.7x heavier	lighter
Strong beam	40% 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 ABS (bulk/injection) or Aluminum 2024-T351?

Aluminum 2024-T351 conducts heat better: 120 W/m·K against 0.17 W/m·K for Plastic ABS (bulk/injection).

Which expands less with temperature?

Aluminum 2024-T351 expands less: 22.9 µm/m·K against 95 µm/m·K for Plastic ABS (bulk/injection).

Among 59 materials

Stiffness against density

Strength against density