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A359/SiC/20p vs AZ91/SiC/15p

Composite · grade comparison

A359/SiC/20p and AZ91/SiC/15p are both composite grades. A359/SiC/20p is the stronger of the two: yield strength 310 MPa (45 ksi) against 130 MPa (18.9 ksi) for AZ91/SiC/15p, about 138% more; tensile strength follows at 340 MPa (49.3 ksi) vs 200 MPa (29 ksi). In exchange, AZ91/SiC/15p is the more ductile: elongation 1.2% versus 0.5% for A359/SiC/20p. AZ91/SiC/15p is lighter (2.02 g/cm³ vs 2.77 g/cm³ for A359/SiC/20p) and A359/SiC/20p is stiffer (98.6 GPa vs 57 GPa). On the shop floor, AZ91/SiC/15p machines more easily (fair vs not recommended).

A359/SiC/20pChoose it when strength drives the design, or when the part sees heat.

AZ91/SiC/15pChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

A359/SiC/20p vs AZ91/SiC/15p: properties

A359/SiC/20pAZ91/SiC/15p

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

98.6 GPa14.3 Msi
57 GPa8.3 Msi

Shear Modulus

38 GPa5.5 Msi
21.8 GPa3.2 Msi

Bulk Modulus

82 GPa11.9 Msi
50 GPa7.3 Msi

Poisson's Ratio

0.32
0.31

Tensile Strength (Ultimate)

340 MPa49.3 ksi
200 MPa29 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
130 MPa18.9 ksi

Elongation at Break

0.5%
1.2%

Compressive Strength

480 MPa69.6 ksi
400 MPa58 ksi

Compressive Modulus

99 GPa14.4 Msi
57 GPa8.3 Msi

Flexural Strength

480 MPa69.6 ksi
330 MPa47.9 ksi

Flexural Modulus

98 GPa14.2 Msi
56 GPa8.1 Msi

Shear Strength

210 MPa30.5 ksi
145 MPa21 ksi

Fracture Toughness (K_IC)

15 MPa·√m13.7 ksi·√in
11 MPa·√m10 ksi·√in

Physical

Density and transition temperatures.

Density

2.77 g/cm³0.1 lb/in³
2.02 g/cm³0.07 lb/in³

Thermal

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

Thermal Conductivity

180 W/m·K104 BTU/hr·ft·°F
75 W/m·K43.3 BTU/hr·ft·°F

Specific Heat Capacity

840 J/kg·K0.2 BTU/lb·°F
970 J/kg·K0.23 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

17.5 µm/m·K9.7 µin/in·°F
21.5 µm/m·K11.9 µin/in·°F

Max Service Temperature (continuous)

200°C392 °F
150°C302 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Max Service Temperature (short-term)

300°C572 °F
200°C392 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

6×10⁻⁸ Ω·m2.36 µΩ·in
1.8×10⁻⁷ Ω·m7.09 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
15 / 100

UV / Weathering Resistance

95 / 100
45 / 100

Manufacturability

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

Machinability

12 / 100
45 / 100

Same in both: Polishability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

190 MJ/kg81,685 BTU/lb
300 MJ/kg128,977 BTU/lb

Embodied Carbon (primary production)

13 kg CO₂/kg
30 kg CO₂/kg

Embodied Water

1,100 L/kg132 gal/lb
500 L/kg59.9 gal/lb

Typical Recycled Content

15%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

123 kN·m/kg
99 kN·m/kg

Specific Stiffness (E / density)

35.6 MN·m/kg
28.2 MN·m/kg

Modulus of Resilience

487 kJ/m³
148 kJ/m³

Thermal Diffusivity

77.4 mm²/s
38.3 mm²/s

Thermal Shock Resistance Index

35
12

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 scaleA359/SiC/20pAZ91/SiC/15p

Manufacturing and finishing

CapabilityA359/SiC/20pAZ91/SiC/15p
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

A359/SiC/20p vs AZ91/SiC/15p — frequently asked

Is A359/SiC/20p stronger than AZ91/SiC/15p?

Yes. A359/SiC/20p has a typical yield strength of 310 MPa (45 ksi) against 130 MPa (18.9 ksi) for AZ91/SiC/15p — about 138% more. Tensile strength is 340 MPa (49.3 ksi) vs 200 MPa (29 ksi).

Which is cheaper, A359/SiC/20p or AZ91/SiC/15p?

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, A359/SiC/20p or AZ91/SiC/15p?

AZ91/SiC/15p. Its machinability rates fair (45/100) against not recommended (12/100) for A359/SiC/20p.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A359/SiC/20p and AZ91/SiC/15p 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.