Aluminum 6061-T6 vs. Plastic PLA

Compare Aluminum 6061-T6 vs. Plastic PLA strength, stiffness, weight and thermal properties.

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Mechanical
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Yield strength	276MPasourcetypical, 0.2% offset, .500 in dia specimen	52.5MPasourcetypical
Ultimate tensile strength	310MPasourcetypical	52.5MPasourcetypical, peak stress (= stress at yield)
Flexural strength	not sourced	96.8MPasourcetypical
Elongation at break	17%sourcetypical, in 4D, 0.500 in dia specimen	7.8%sourcetypical
Young's modulus (stiffness)	68.3GPasourcetypical21x stiffer	3.25GPasourcetypical
Density	2,700kg/m³sourcenominal	1,240kg/m³sourcetypical
Strength to weight	102kN·m/kg2.41x higher	42.3kN·m/kg
Stiffness to weight	25.3MN·m/kg9.65x higher	2.62MN·m/kg
Poisson's ratio	0.33sourcetypical (handbook physical constant)	not sourced
Shear modulus	25.7GPa	not sourced
Bulk modulus	67GPa	not sourced
Speed of sound	5,030m/s	1,619m/s
Thermal
Thermal conductivity	167W/m·Ksourcetypical, 20 °C	0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C
Thermal expansion	23.6µm/m·Ksourcetypical, mean 20-100 °C	not sourced
100 mm part over a 50 °C swing	118µm growth	not sourced
Specific heat	896J/kg·Ksourcetypical, at 100 °C	1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C
Heats up and cools (diffusivity)	69mm²/s790x faster	0.0874mm²/s
Thermal shock resistance	19,159W/m	not sourced
Melting point	582–652°Csourcesolidus-liquidus	152°Csourcetypical
Glass transition	not sourced	59.1°Csourcetypical
Max service temperature	not sourced	58.8°CsourceHDT 0.455 MPa (printed specimens)
Values for	6061-T6/T651, Kaiser Aluminum typical properties; Poisson from MIL-HDBK-5J	Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS dated April 20, 2022.

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.

Plastic PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is Aluminum 6061-T6 stronger than Plastic PLA?

Aluminum 6061-T6 is stronger: its yield strength is 276 MPa against 52.5 MPa for Plastic PLA (5.26x).

Which is lighter, Aluminum 6061-T6 or Plastic PLA?

Plastic PLA is lighter: 1,240 kg/m³ against 2,700 kg/m³ for Aluminum 6061-T6.

Which is stiffer, Aluminum 6061-T6 or Plastic PLA?

Aluminum 6061-T6 is stiffer: Young's modulus 68.3 GPa against 3.25 GPa for Plastic PLA, so the same part in Aluminum 6061-T6 deflects less under the same load.

Which is lighter for the same job, Aluminum 6061-T6 or Plastic PLA?

For the same stiffness or strength: Aluminum 6061-T6 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum 6061-T6	Plastic PLA
Stiff rod or tie (tension)	lighter	9.65x heavier
Stiff beam (bending)	lighter	2.11x heavier
Stiff panel or plate	lighter	27% heavier
Strong rod or tie	lighter	2.41x heavier
Strong beam	lighter	39% heavier
Strong panel or plate	lighter	5% heavier

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 6061-T6 or Plastic PLA?

Aluminum 6061-T6 conducts heat better: 167 W/m·K against 0.13 W/m·K for Plastic PLA.

Among 72 materials

Stiffness against density

Strength against density