300°Csourceproducer's maximum application temperature (optical components)
Values for
A380 aluminium high-pressure die-casting alloy, typical properties; Rheocast Company (aluminium die caster, Germantown WI) A380 alloy data page.
Synthetic single-crystal silicon (cubic, diamond structure), Korth Kristalle (crystal grower) material data; Korth usually supplies Floating Zone (FZ) material, Czochralski (Cz) also offered. Silicon is elastically anisotropic; the producer quotes one modulus and the solver is isotropic.
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 A380 stronger than Silicon?
Aluminum A380 is stronger: its yield strength is 160 MPa against tensile strength 130 MPa for Silicon (23%).
Which is lighter, Aluminum A380 or Silicon?
Silicon is lighter: 2,329 kg/m³ against 2,713 kg/m³ for Aluminum A380.
Which is stiffer, Aluminum A380 or Silicon?
Silicon is stiffer: Young's modulus 131 GPa against 71 GPa for Aluminum A380, so the same part in Silicon deflects less under the same load.
Which is lighter for the same job, Aluminum A380 or Silicon?
For the same stiffness or strength: Aluminum A380 is lighter for a strong rod or tie; Silicon is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong beam, strong panel or plate.
Part that must be
Aluminum A380
Silicon
Stiff rod or tie (tension)
2.15x heavier
lighter
Stiff beam (bending)
1.58x heavier
lighter
Stiff panel or plate
43% heavier
lighter
Strong rod or tie
lighter
6% heavier
Strong beam
1% heavier
lighter
Strong panel or plate
5% 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 A380 or Silicon?
Silicon conducts heat better: 163 W/m·K against 96.2 W/m·K for Aluminum A380.
Which expands less with temperature?
Silicon expands less: 2.62 µm/m·K against 21.8 µm/m·K for Aluminum A380.