1100-O (annealed) commercially pure aluminium, Kaiser Aluminum Tube & Pipe Alloy 1100 Technical Data (Rev. 05/06), typical properties; specific heat from Hydro EN AW-1050A (99.5% Al) extruded-products datasheet (10/2018).
Ultimaker TPU 95A, 3D-printed specimens, XY (flat); 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 (file v5.00), April 29, 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 TPU is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Aluminum 1100-O stronger than Plastic TPU?
Aluminum 1100-O is stronger: its yield strength is 35 MPa against tensile strength 23.7 MPa for Plastic TPU (48%).
Which is lighter, Aluminum 1100-O or Plastic TPU?
Plastic TPU is lighter: 1,220 kg/m³ against 2,710 kg/m³ for Aluminum 1100-O.
Which is stiffer, Aluminum 1100-O or Plastic TPU?
Aluminum 1100-O is stiffer: Young's modulus 69 GPa against 0.067 GPa for Plastic TPU, so the same part in Aluminum 1100-O deflects less under the same load.
Which is lighter for the same job, Aluminum 1100-O or Plastic TPU?
For the same stiffness or strength: Aluminum 1100-O is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic TPU is lighter for a strong rod or tie, strong beam, strong panel or plate.
Part that must be
Aluminum 1100-O
Plastic TPU
Stiff rod or tie (tension)
lighter
464x heavier
Stiff beam (bending)
lighter
14.4x heavier
Stiff panel or plate
lighter
4.55x heavier
Strong rod or tie
1.5x heavier
lighter
Strong beam
1.71x heavier
lighter
Strong panel or plate
1.83x 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).