Aluminum ADC12 vs. Plastic PBT GF30

Compare Aluminum ADC12 vs. Plastic PBT GF30 strength, stiffness, weight and thermal properties.

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Plastic PBT GF30Bulk polymer (molded or machined)

Mechanical
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Yield strength	149MPasourceone test result, 0.2% proof stress, as cast, ASTM tensile bar (Daiki)	not given (tensile used)
Ultimate tensile strength	345MPasourceone test result, as cast, ASTM tensile bar (Daiki)	140MPasourcestress at break, 23 °C
Flexural strength	not sourced	210MPasourcetypical, 23 °C
Elongation at break	2.3%sourceone test result, as cast, ASTM tensile bar (Daiki)	3%sourcestrain at break, 23 °C
Young's modulus (stiffness)	79.8GPasourcestandard value (S.S.Aluminum)	9.8GPasourcetypical, 23 °C
Density	2,680kg/m³sourcemeasured (Daiki)	1,530kg/m³sourcetypical
Strength to weight	55.6kN·m/kg	91.5kN·m/kg1.65x higher
Stiffness to weight	29.8MN·m/kg4.65x higher	6.41MN·m/kg
Poisson's ratio	not sourced	not sourced
Shear modulus	not sourced	not sourced
Bulk modulus	not sourced	not sourced
Speed of sound	5,457m/s	2,531m/s
Thermal
Thermal conductivity	125W/m·Ksourcemeasured on specimens cut from a 50 x 100 x 5 mm flat die casting (Daiki)	0.27W/m·Ksourcetypical (DIN 52612-1)
Thermal expansion	21µm/m·Ksourcemeasured, temperature range not stated (Daiki)	25µm/m·Ksourcelongitudinal (flow), mean 23-55 °C
100 mm part over a 50 °C swing	105µm growth19% less	125µm growth
Specific heat	911J/kg·Ksourcemeasured (Daiki)	1,050J/kg·Ksourcetypical, 23 °C
Heats up and cools (diffusivity)	51.2mm²/s305x faster	0.168mm²/s
Thermal shock resistance	not sourced	not sourced
Melting point	515–582°Csourcesolidus-liquidus (Daiki)	223°CsourceDSC (ISO 11357)
Max service temperature	not sourced	205°CsourceHDT 1.8 MPa
Values for	JIS ADC12 (Al-Si-Cu, about A383 / EN AC-46100) high-pressure die-casting alloy, as cast; physical properties from Daiki Aluminium Industry (ADC12 ingot producer) measured values; modulus from S.S.Aluminum (ADC12 ingot producer) standard values.	BASF Ultradur B 4300 G6 (PBT, 30% glass fibre), injection moulding grade; product information sheet 09/2026, typical values for uncoloured product at 23 °C.

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 ADC12 stronger than Plastic PBT GF30?

Aluminum ADC12 is stronger: its yield strength is 149 MPa against tensile strength 140 MPa for Plastic PBT GF30 (6%).

Which is lighter, Aluminum ADC12 or Plastic PBT GF30?

Plastic PBT GF30 is lighter: 1,530 kg/m³ against 2,680 kg/m³ for Aluminum ADC12.

Which is stiffer, Aluminum ADC12 or Plastic PBT GF30?

Aluminum ADC12 is stiffer: Young's modulus 79.8 GPa against 9.8 GPa for Plastic PBT GF30, so the same part in Aluminum ADC12 deflects less under the same load.

Which is lighter for the same job, Aluminum ADC12 or Plastic PBT GF30?

For the same stiffness or strength: Aluminum ADC12 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic PBT GF30 is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum ADC12	Plastic PBT GF30
Stiff rod or tie (tension)	lighter	4.65x heavier
Stiff beam (bending)	lighter	1.63x heavier
Stiff panel or plate	lighter	15% heavier
Strong rod or tie	1.65x heavier	lighter
Strong beam	1.68x heavier	lighter
Strong panel or plate	1.7x 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 ADC12 or Plastic PBT GF30?

Aluminum ADC12 conducts heat better: 125 W/m·K against 0.27 W/m·K for Plastic PBT GF30.

Which expands less with temperature?

Aluminum ADC12 expands less: 21 µm/m·K against 25 µm/m·K for Plastic PBT GF30.

Among 72 materials

Stiffness against density

Strength against density