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Al2O3/SiCw vs C/SiC

Composite · grade comparison

Al2O3/SiCw and C/SiC are both composite grades. Al2O3/SiCw is the stronger of the two: tensile strength 350 MPa (50.8 ksi) against 150 MPa (21.8 ksi) for C/SiC, about 133% more. In exchange, C/SiC is the more ductile: elongation 0.3% versus 0.1% for Al2O3/SiCw. C/SiC is lighter (2.1 g/cm³ vs 3.74 g/cm³ for Al2O3/SiCw) and Al2O3/SiCw is stiffer (390 GPa vs 65 GPa).

Al2O3/SiCwChoose it when strength drives the design.

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

Al2O3/SiCw vs C/SiC: properties

Al2O3/SiCwC/SiC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

390 GPa56.6 Msi
65 GPa9.4 Msi

Shear Modulus

160 GPa23.2 Msi
25 GPa3.6 Msi

Bulk Modulus

250 GPa36.3 Msi
—

Poisson's Ratio

0.24
0.17

Tensile Strength (Ultimate)

350 MPa50.8 ksi
150 MPa21.8 ksi

Elongation at Break

0.1%
0.3%

Compressive Strength

3,000 MPa435 ksi
500 MPa72.5 ksi

Flexural Strength

750 MPa109 ksi
220 MPa31.9 ksi

Flexural Modulus

390 GPa56.6 Msi
70 GPa10.2 Msi

Shear Strength

300 MPa43.5 ksi
28 MPa4.1 ksi

Fracture Toughness (K_IC)

8 MPa·√m7.3 ksi·√in
15 MPa·√m13.7 ksi·√in

Physical

Density and transition temperatures.

Density

3.74 g/cm³0.14 lb/in³
2.1 g/cm³0.08 lb/in³

Water Absorption (24 h)

0%
0.2%

Thermal

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

Thermal Conductivity

32 W/m·K18.5 BTU/hr·ft·°F
20 W/m·K11.6 BTU/hr·ft·°F

Specific Heat Capacity

800 J/kg·K0.19 BTU/lb·°F
750 J/kg·K0.18 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

6.6 µm/m·K3.7 µin/in·°F
2.5 µm/m·K1.4 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
1,650°C3,002 °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
0.001 Ω·m39,370 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
80 / 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
10 / 100

Polishability

80 / 100
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

160 MJ/kg68,788 BTU/lb
700 MJ/kg300,946 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
45 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
71 kN·m/kg

Specific Stiffness (E / density)

104.3 MN·m/kg
31 MN·m/kg

Thermal Diffusivity

10.7 mm²/s
12.7 mm²/s

Thermal Shock Resistance Index

4
18

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

Al2O3/SiCw vs C/SiC — frequently asked

Is Al2O3/SiCw stronger than C/SiC?

Yes. Al2O3/SiCw has a typical tensile strength of 350 MPa (50.8 ksi) against 150 MPa (21.8 ksi) for C/SiC — about 133% more.

Which is cheaper, Al2O3/SiCw or C/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.

Which is easier to machine, Al2O3/SiCw or C/SiC?

C/SiC, by a small margin. Both rate not recommended for machinability — 10/100 against 5/100 for Al2O3/SiCw.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Al2O3/SiCw and C/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.