Plastic ABS (bulk/injection) vs. Silicon

Compare Plastic ABS (bulk/injection) vs. Silicon strength, stiffness, weight and thermal properties.

Change either side

Plastic ABS (bulk/injection)Bulk polymer (molded or machined)

SiliconGrown single crystal

Mechanical
Try it on a partA sample part to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD
Yield strength	45MPasourcetypical, tensile stress at yield 23 °C	not given (tensile used)
Ultimate tensile strength	not sourced	130MPasourcemodulus of rupture (bending fracture stress); brittle, no yield point
Flexural strength	65MPasourcetypical, 23 °C	130MPasourcemodulus of rupture
Elongation at break	10%sourcenominal strain at break, 23 °C	not sourced
Young's modulus (stiffness)	2.3GPasourcetypical	131GPasourcetypical (single quoted value of an anisotropic crystal)
Density	1,040kg/m³sourcetypical2.24x lighter	2,329kg/m³sourcetypical
Strength to weight	43.3kN·m/kg	55.8kN·m/kg29% higher
Stiffness to weight	2.21MN·m/kg	56.2MN·m/kg25.4x higher
Poisson's ratio	0.39sourcetypical, ABS family (Covestro Part and Mold Design guide, Table 3-1)	0.221sourcetypical
Shear modulus	0.827GPa	53.6GPa64.8x stiffer in shear
Bulk modulus	3.48GPa	78.3GPa
Speed of sound	1,487m/s	7,500m/s
Thermal
Thermal conductivity	0.17W/m·Ksourcetypical	163W/m·Ksourcetypical at 313 K (40 °C)
Thermal expansion	80–110µm/m·Ksourcerange	2.62µm/m·Ksourcetypical at 300 K
100 mm part over a 50 °C swing	475µm growth	13.1µm growth36.3x less
Specific heat	not sourced	732J/kg·Ksourcetypical
Heats up and cools (diffusivity)	not sourced	95.6mm²/s
Thermal shock resistance	21.4W/m	48,095W/m2,252x more resistant
Melting point	not sourced	1,412°Csourcetypical
Max service temperature	94°CsourceHDT 1.8 MPa (annealed 4 h/80 °C)	300°Csourceproducer's maximum application temperature (optical components)
Values for	INEOS Styrolution Terluran GP-22 general-purpose injection-molding ABS, ISO typical values (TDS revision 08/01/2022)	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 ABS (bulk/injection) stronger than Silicon?

Silicon is stronger: its tensile strength is 130 MPa against yield strength 45 MPa for Plastic ABS (bulk/injection) (2.89x).

Which is lighter, Plastic ABS (bulk/injection) or Silicon?

Plastic ABS (bulk/injection) is lighter: 1,040 kg/m³ against 2,329 kg/m³ for Silicon.

Which is stiffer, Plastic ABS (bulk/injection) or Silicon?

Silicon is stiffer: Young's modulus 131 GPa against 2.3 GPa for Plastic ABS (bulk/injection), so the same part in Silicon deflects less under the same load.

Which is lighter for the same job, Plastic ABS (bulk/injection) or Silicon?

For the same stiffness or strength: Plastic ABS (bulk/injection) is lighter for a strong beam, 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.

Part that must be	Plastic ABS (bulk/injection)	Silicon
Stiff rod or tie (tension)	25.4x heavier	lighter
Stiff beam (bending)	3.37x heavier	lighter
Stiff panel or plate	1.72x heavier	lighter
Strong rod or tie	29% heavier	lighter
Strong beam	lighter	10% heavier
Strong panel or plate	lighter	32% 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 ABS (bulk/injection) or Silicon?

Silicon conducts heat better: 163 W/m·K against 0.17 W/m·K for Plastic ABS (bulk/injection).

Which expands less with temperature?

Silicon expands less: 2.62 µm/m·K against 95 µm/m·K for Plastic ABS (bulk/injection).

Among 72 materials

Stiffness against density

Strength against density