Aluminum 6063-T6 vs. Plastic PBT GF30

Compare Aluminum 6063-T6 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	215MPasourcetypical, T6, 0.0625 in specimen	not given (tensile used)
Ultimate tensile strength	240MPasourcetypical, T6	140MPasourcestress at break, 23 °C
Flexural strength	not sourced	210MPasourcetypical, 23 °C
Elongation at break	12%sourcetypical, T6, in 4D	3%sourcestrain at break, 23 °C
Young's modulus (stiffness)	69GPasourcetypical	9.8GPasourcetypical, 23 °C
Density	2,700kg/m³sourcenominal, 20 °C	1,530kg/m³sourcetypical
Strength to weight	79.6kN·m/kg	91.5kN·m/kg15% higher
Stiffness to weight	25.6MN·m/kg3.99x 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	5,055m/s	2,531m/s
Thermal
Thermal conductivity	201W/m·Ksourcetypical, T6, 20 °C	0.27W/m·Ksourcetypical (DIN 52612-1)
Thermal expansion	23.4µm/m·Ksourcetypical, mean 20-100 °C	25µm/m·Ksourcelongitudinal (flow), mean 23-55 °C
100 mm part over a 50 °C swing	117µm growth7% less	125µm growth
Specific heat	901J/kg·Ksourcetypical, 20 °C (Hydro EN AW-6063)	1,050J/kg·Ksourcetypical, 23 °C
Heats up and cools (diffusivity)	82.6mm²/s492x faster	0.168mm²/s
Thermal shock resistance	not sourced	not sourced
Melting point	615–655°Csourcemelting range	223°CsourceDSC (ISO 11357)
Max service temperature	not sourced	205°CsourceHDT 1.8 MPa
Values for	6063-T6 extruded tube, Kaiser Aluminum Tube & Pipe Alloy 6063 Technical Data (Rev. 05/06), typical properties; specific heat from Hydro EN AW-6063 extruded-products datasheet (Rev.4, 03/2023).	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 6063-T6 stronger than Plastic PBT GF30?

Aluminum 6063-T6 is stronger: its yield strength is 215 MPa against tensile strength 140 MPa for Plastic PBT GF30 (1.54x).

Which is lighter, Aluminum 6063-T6 or Plastic PBT GF30?

Plastic PBT GF30 is lighter: 1,530 kg/m³ against 2,700 kg/m³ for Aluminum 6063-T6.

Which is stiffer, Aluminum 6063-T6 or Plastic PBT GF30?

Aluminum 6063-T6 is stiffer: Young's modulus 69 GPa against 9.8 GPa for Plastic PBT GF30, so the same part in Aluminum 6063-T6 deflects less under the same load.

Which is lighter for the same job, Aluminum 6063-T6 or Plastic PBT GF30?

For the same stiffness or strength: Aluminum 6063-T6 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 6063-T6	Plastic PBT GF30
Stiff rod or tie (tension)	lighter	3.99x heavier
Stiff beam (bending)	lighter	1.5x heavier
Stiff panel or plate	lighter	9% heavier
Strong rod or tie	15% heavier	lighter
Strong beam	33% heavier	lighter
Strong panel or plate	42% 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 6063-T6 or Plastic PBT GF30?

Aluminum 6063-T6 conducts heat better: 201 W/m·K against 0.27 W/m·K for Plastic PBT GF30.

Which expands less with temperature?

Aluminum 6063-T6 expands less: 23.4 µm/m·K against 25 µm/m·K for Plastic PBT GF30.

Among 72 materials

Stiffness against density

Strength against density