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.
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 ADC12 stronger than Plastic TPU?
Aluminum ADC12 is stronger: its yield strength is 149 MPa against tensile strength 23.7 MPa for Plastic TPU (6.29x).
Which is lighter, Aluminum ADC12 or Plastic TPU?
Plastic TPU is lighter: 1,220 kg/m³ against 2,680 kg/m³ for Aluminum ADC12.
Which is stiffer, Aluminum ADC12 or Plastic TPU?
Aluminum ADC12 is stiffer: Young's modulus 79.8 GPa against 0.067 GPa for Plastic TPU, so the same part in Aluminum ADC12 deflects less under the same load.
Which is lighter for the same job, Aluminum ADC12 or Plastic TPU?
For the same stiffness or strength: Aluminum ADC12 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 ADC12
Plastic TPU
Stiff rod or tie (tension)
lighter
542x heavier
Stiff beam (bending)
lighter
15.7x heavier
Stiff panel or plate
lighter
4.83x heavier
Strong rod or tie
lighter
2.86x heavier
Strong beam
lighter
1.55x heavier
Strong panel or plate
lighter
14% 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).