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Kevlar 49 vs Quartz Fiber Composite

Composite · grade comparison

Kevlar 49 and Quartz Fiber Composite are both composite grades. Kevlar 49 is the stronger of the two: tensile strength 3,000 MPa (435 ksi) against 500 MPa (72.5 ksi) for Quartz Fiber Composite, about 6.0 times as much. Kevlar 49 is the more ductile: elongation 2.4% versus 2% for Quartz Fiber Composite. Kevlar 49 is lighter (1.44 g/cm³ vs 1.75 g/cm³ for Quartz Fiber Composite) and Kevlar 49 is stiffer (112 GPa vs 25 GPa).

Kevlar 49Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

Kevlar 49 vs Quartz Fiber Composite: properties

Kevlar 49Quartz Fiber Composite

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

112 GPa16.2 Msi
25 GPa3.6 Msi

Shear Modulus

2.9 GPa0.42 Msi
4 GPa0.58 Msi

Poisson's Ratio

0.36
0.16

Tensile Strength (Ultimate)

3,000 MPa435 ksi
500 MPa72.5 ksi

Elongation at Break

2.4%
2%

Compressive Strength

—
400 MPa58 ksi

Compressive Modulus

—
24 GPa3.5 Msi

Flexural Strength

—
550 MPa79.8 ksi

Flexural Modulus

—
24 GPa3.5 Msi

Shear Strength

—
45 MPa6.5 ksi

Physical

Density and transition temperatures.

Density

1.44 g/cm³0.05 lb/in³
1.75 g/cm³0.06 lb/in³

Glass Transition (Tg)

360°C680 °F
135°C275 °F

Water Absorption (Saturation)

4%
0.6%

Water Absorption (24 h)

—
0.15%

Thermal

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

Thermal Conductivity

0.04 W/m·K0.02 BTU/hr·ft·°F
0.4 W/m·K0.23 BTU/hr·ft·°F

Specific Heat Capacity

1,420 J/kg·K0.34 BTU/lb·°F
900 J/kg·K0.21 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

-2 µm/m·K-1.1 µin/in·°F
4 µm/m·K2.2 µin/in·°F

Max Service Temperature (continuous)

160°C320 °F
150°C302 °F

Limiting Oxygen Index

29%
32%

Max Service Temperature (short-term)

250°C482 °F
200°C392 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Dielectric Constant (1 MHz)

4
3.2

Dissipation Factor (1 MHz)

0.02
0.01

Dielectric Strength

—
20 kV/mm508 V/mil

Surface Resistivity

—
1×10¹⁴ Ω

Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Volume Resistivity 1×10¹⁵ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
85 / 100

UV / Weathering Resistance

20 / 100
55 / 100

Manufacturability

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

Polishability

—
35 / 100

Same in both: Machinability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

280 MJ/kg120,378 BTU/lb
320 MJ/kg137,575 BTU/lb

Embodied Carbon (primary production)

17 kg CO₂/kg
22 kg CO₂/kg

Embodied Water

—
250 L/kg30 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2,083 kN·m/kg
286 kN·m/kg

Specific Stiffness (E / density)

77.8 MN·m/kg
14.3 MN·m/kg

Thermal Diffusivity

0 mm²/s
0.3 mm²/s

Thermal Shock Resistance Index

-1
2

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

CapabilityKevlar 49Quartz Fiber Composite
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Kevlar 49 vs Quartz Fiber Composite — frequently asked

Is Kevlar 49 stronger than Quartz Fiber Composite?

Yes. Kevlar 49 has a typical tensile strength of 3,000 MPa (435 ksi) against 500 MPa (72.5 ksi) for Quartz Fiber Composite — about 6.0 times as much.

Which is cheaper, Kevlar 49 or Quartz Fiber Composite?

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 Kevlar 49 over Quartz Fiber Composite?

Pick Kevlar 49 when strength drives the design, or when the part is bent, formed or impact-loaded.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Kevlar 49 and Quartz Fiber Composite 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.