300°Csourceproducer's maximum application temperature (optical components)
Values for
LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values
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 Plastic HDPE stronger than Silicon?
Silicon is stronger: its tensile strength is 130 MPa against yield strength 24 MPa for Plastic HDPE (5.42x).
Which is lighter, Plastic HDPE or Silicon?
Plastic HDPE is lighter: 950 kg/m³ against 2,329 kg/m³ for Silicon.
Which is stiffer, Plastic HDPE or Silicon?
Silicon is stiffer: Young's modulus 131 GPa against 0.9 GPa for Plastic HDPE, so the same part in Silicon deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Silicon?
For the same stiffness or strength: Plastic HDPE is lighter for a strong panel or plate; Silicon is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam.
Part that must be
Plastic HDPE
Silicon
Stiff rod or tie (tension)
59.4x heavier
lighter
Stiff beam (bending)
4.92x heavier
lighter
Stiff panel or plate
2.15x heavier
lighter
Strong rod or tie
2.21x heavier
lighter
Strong beam
26% heavier
lighter
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, Plastic HDPE or Silicon?
Silicon conducts heat better: 163 W/m·K against 0.445 W/m·K for Plastic HDPE.
Which expands less with temperature?
Silicon expands less: 2.62 µm/m·K against 120 µm/m·K for Plastic HDPE.