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Al2O3/SiCw vs SiC/SiC

Composite · grade comparison

Al2O3/SiCw and SiC/SiC are both composite grades. Al2O3/SiCw is the stronger of the two: tensile strength 350 MPa (50.8 ksi) against 300 MPa (43.5 ksi) for SiC/SiC, about 17% more. In exchange, SiC/SiC is the more ductile: elongation 0.6% versus 0.1% for Al2O3/SiCw. SiC/SiC is lighter (2.5 g/cm³ vs 3.74 g/cm³ for Al2O3/SiCw) and Al2O3/SiCw is stiffer (390 GPa vs 230 GPa).

Al2O3/SiCwChoose it when strength drives the design.

SiC/SiCChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

Al2O3/SiCw vs SiC/SiC: properties

Al2O3/SiCwSiC/SiC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

390 GPa56.6 Msi
230 GPa33.4 Msi

Shear Modulus

160 GPa23.2 Msi
95 GPa13.8 Msi

Bulk Modulus

250 GPa36.3 Msi
120 GPa17.4 Msi

Poisson's Ratio

0.24
0.18

Tensile Strength (Ultimate)

350 MPa50.8 ksi
300 MPa43.5 ksi

Elongation at Break

0.1%
0.6%

Compressive Strength

3,000 MPa435 ksi
600 MPa87 ksi

Flexural Strength

750 MPa109 ksi
420 MPa60.9 ksi

Flexural Modulus

390 GPa56.6 Msi
210 GPa30.5 Msi

Shear Strength

300 MPa43.5 ksi
38 MPa5.5 ksi

Fracture Toughness (K_IC)

8 MPa·√m7.3 ksi·√in
25 MPa·√m22.8 ksi·√in

Compressive Modulus

—
230 GPa33.4 Msi

Physical

Density and transition temperatures.

Density

3.74 g/cm³0.14 lb/in³
2.5 g/cm³0.09 lb/in³

Water Absorption (24 h)

0%
—

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

32 W/m·K18.5 BTU/hr·ft·°F
15 W/m·K8.7 BTU/hr·ft·°F

Specific Heat Capacity

800 J/kg·K0.19 BTU/lb·°F
700 J/kg·K0.17 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

6.6 µm/m·K3.7 µin/in·°F
4.3 µm/m·K2.4 µin/in·°F

Max Service Temperature (continuous)

1,200°C2,192 °F
1,350°C2,462 °F

Max Service Temperature (short-term)

1,500°C2,732 °F
1,600°C2,912 °F

Same in both: Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

0.5 Ω·m1.97×10⁷ µΩ·in
0.1 Ω·m3,937,000 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
88 / 100

Same in both: UV / Weathering Resistance 100 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

5 / 100
4 / 100

Polishability

80 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

160 MJ/kg68,788 BTU/lb
1,500 MJ/kg644,885 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
110 kg CO₂/kg

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

94 kN·m/kg
120 kN·m/kg

Specific Stiffness (E / density)

104.3 MN·m/kg
92 MN·m/kg

Thermal Diffusivity

10.7 mm²/s
8.6 mm²/s

Thermal Shock Resistance Index

4
5

Strength versus weight

Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

1101001,000510Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilityAl2O3/SiCwSiC/SiC
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Al2O3/SiCw vs SiC/SiC — frequently asked

Is Al2O3/SiCw stronger than SiC/SiC?

Yes. Al2O3/SiCw has a typical tensile strength of 350 MPa (50.8 ksi) against 300 MPa (43.5 ksi) for SiC/SiC — about 17% more.

Which is cheaper, Al2O3/SiCw or SiC/SiC?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

When should I choose Al2O3/SiCw over SiC/SiC?

Pick Al2O3/SiCw when strength drives the design. Pick SiC/SiC when the part is bent, formed or impact-loaded, or when weight is the constraint.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Al2O3/SiCw and SiC/SiC side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.