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.
ATI 316 (UNS S31600), annealed 1.0 mm sheet, ATI technical data sheet (2012); Poisson's ratio from the Nickel Institute/SCI structural stainless design manual
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 Stainless Steel 316?
Stainless Steel 316 is stronger: its yield strength is 265 MPa against 149 MPa for Aluminum ADC12 (1.78x).
Which is lighter, Aluminum ADC12 or Stainless Steel 316?
Aluminum ADC12 is lighter: 2,680 kg/m³ against 8,027 kg/m³ for Stainless Steel 316.
Which is stiffer, Aluminum ADC12 or Stainless Steel 316?
Stainless Steel 316 is stiffer: Young's modulus 200 GPa against 79.8 GPa for Aluminum ADC12, so the same part in Stainless Steel 316 deflects less under the same load.
Which is lighter for the same job, Aluminum ADC12 or Stainless Steel 316?
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
Stainless Steel 316
Stiff rod or tie (tension)
lighter
20% heavier
Stiff beam (bending)
lighter
1.89x heavier
Stiff panel or plate
lighter
2.21x heavier
Strong rod or tie
lighter
1.68x heavier
Strong beam
lighter
2.04x heavier
Strong panel or plate
lighter
2.25x 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 ADC12 or Stainless Steel 316?
Aluminum ADC12 conducts heat better: 125 W/m·K against 14.6 W/m·K for Stainless Steel 316.
Which expands less with temperature?
Stainless Steel 316 expands less: 16.5 µm/m·K against 21 µm/m·K for Aluminum ADC12.