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Carbon Fiber · matrix · default condition

Carbon Fiber Epoxy Matrix

Properties of the Epoxy Matrix condition, compared with the other Carbon Fiber grades.

Default general-purpose CFRP: 3K twill/plain woven fabric in 120–180 °C cure epoxy, balanced 0/90 properties, panels and plates.

CNC machiningSheet metalPremium cost $$$

What is Carbon Fiber Epoxy Matrix?

Carbon Fiber Epoxy Matrix is Carbon Fiber in the Epoxy Matrix condition — default general-purpose CFRP: 3K twill/plain woven fabric in 120–180 °C cure epoxy, balanced 0/90 properties, panels and plates. Carbon Fiber Epoxy Matrix has a tensile strength of 650 MPa (94.3 ksi), stronger than 68% of composite grades. Elongation at break is 1.2% and the elastic modulus is 70 GPa (10.2 Msi). Carbon Fiber Epoxy Matrix has a density of 1.55 g/cm³ (0.056 lb/in³), lighter than 58% of composite grades. Its glass-transition temperature is 125°C (257 °F).

Advantages

  • Low, predictable mold shrinkage — 0.1%, better than 100% of composite grades
  • Polishes to a fine finish — 60/100, better than 89% of composite grades
  • Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 85% of composite grades
  • Low moisture uptake — 0.1%, better than 85% of composite grades

Limitations

  • Limited service temperature — 120°C (248 °F), worse than 79% of composite grades

Carbon Fiber Epoxy Matrix properties

Typical room-temperature values for Carbon Fiber Epoxy Matrix — 12 properties are specific to this condition; the rest are grade-level values shared by every Carbon Fiber grade. Each bar shows where the value sits among the composite grades in FabDigit's library — further right is higher.

Physical4

Carbon Fiber Epoxy Matrix has a density of 1.55 g/cm³ (0.056 lb/in³), lighter than 58% of composite grades. Its glass-transition temperature is 125°C (257 °F).

Density1.55 g/cm³0.06 lb/in³
Glass Transition (Tg)125°C257 °F
Water Absorption (24 h)0.1%
Water Absorption (Saturation)1%

Mechanical11

Carbon Fiber Epoxy Matrix has a tensile strength of 650 MPa (94.3 ksi), stronger than 68% of composite grades. Elongation at break is 1.2% and the elastic modulus is 70 GPa (10.2 Msi).

Elastic (Young's) Modulus70 GPa10.2 Msi
Shear Modulus5 GPa0.73 Msi
Poisson's Ratio0.1
Tensile Strength (Ultimate)650 MPa94.3 ksi
Elongation at Break1.2%
Compressive Strength570 MPa82.7 ksi
Compressive Modulus62 GPa9 Msi
Flexural Strength800 MPa116 ksi
Flexural Modulus60 GPa8.7 Msi
Shear Strength75 MPa10.9 ksi
Fracture Toughness (K_IC)30 MPa·√m27.3 ksi·√in

Thermal9

Carbon Fiber Epoxy Matrix is rated for continuous service to 120°C (248 °F). It conducts heat at 5 W/m·K (2.89 BTU/hr·ft·°F), better than 63% of composite grades. Thermal expansion is 2 µm/m·K (1.11 µin/in·°F).

Thermal Conductivity5 W/m·K2.9 BTU/hr·ft·°F
Specific Heat Capacity900 J/kg·K0.21 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)2 µm/m·K1.1 µin/in·°F
Max Service Temperature (continuous)120°C248 °F
Min Service Temperature-100°C-148 °F
Heat Deflection Temp. @ 1.8 MPa130°C266 °F
Flammability (UL 94)Standard epoxy laminate burns (≈HB); phenolic or FR-epoxy prepregs reach V-0 with low smoke
Limiting Oxygen Index32%
Max Service Temperature (short-term)180°C356 °F

Electrical3

Carbon Fiber Epoxy Matrix has an electrical resistivity of 0.0015 Ω·m.

Electrical Resistivity0.0015 Ω·m59,055 µΩ·in
Volume Resistivity0.15 Ω·cm
Surface Resistivity100 Ω

Chemical & Environmental3

Corrosion resistance is excellent (85/100), better than 65% of composite grades. UV resistance is fair.

Corrosion ResistanceExcellent85/100
UV / Weathering ResistanceFair40/100
Chemical Resistance SummaryFibers are essentially inert; behaviour is set by the matrix. Cured epoxy resists water, fuels, oils, dilute acids and most solvents; attacked by strong oxidising acids, hot alkalis, and swollen by ketones/chlorinated solvents. Long hot-wet exposure lowers matrix-dominated (compression, shear) strength.

Sustainability4

Producing a kilogram of Carbon Fiber Epoxy Matrix takes about 350 MJ of energy and emits 24 kg of CO₂ — more than 74% of composite grades. Typical recycled content is 0%.

Embodied Energy (primary production)350 MJ/kg150,473 BTU/lb
Embodied Carbon (primary production)24 kg CO₂/kg
Embodied Water600 L/kg71.9 gal/lb
Typical Recycled Content0%

Manufacturability3

Carbon Fiber Epoxy Matrix's machinability is fair (35/100, better than 50% of composite grades).

MachinabilityFair35/100
PolishabilityGood60/100
Mold Shrinkage0.1%

Common Calculations4

Specific Strength (UTS / density)calculated419 kN·m/kg
Specific Stiffness (E / density)calculated45.2 MN·m/kg
Thermal Diffusivitycalculated3.6 mm²/s
Thermal Shock Resistance Indexcalculated23

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Other Carbon Fiber grades and fills

Carbon Fiber is also supplied in 7 other conditions. The full side-by-side table is on the Carbon Fiber overview.

Working with Carbon Fiber Epoxy Matrix

Is Carbon Fiber easy to machine?

Use PCD/diamond-coated or diamond-abrasive tooling, high speed and low feed with backing support to avoid delamination and fiber pull-out; vacuum extraction is mandatory (conductive, respirable dust) and coolant/tool wear is the cost driver.

Can Carbon Fiber be welded?

Thermoset CFRP cannot be welded — join by adhesive bonding (peel-ply/abraded surfaces) or bolted joints with generous bearing area; thermoplastic-matrix (PEEK/PA) variants can be induction, resistance or ultrasonically welded.

Can Carbon Fiber be formed, bent or molded?

Formed by prepreg hand layup/AFP with autoclave or press cure (120–180 °C), RTM/infusion of dry fabric, filament winding, pultrusion, or chopped-prepreg compression molding; thermoplastic tapes are stamp-formed above Tm.

What surface finishes work on Carbon Fiber?

Cannot be anodized or plated conventionally; finish by resin/gel surfacing film, filler-primer and 2K clear or paint with UV blocker, and always isolate from aluminium/steel with glass-fiber ply or sealant to prevent galvanic corrosion.

Carbon Fiber chemical composition (wt %)

Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.

ElementSpec limit (wt %)Nominal
carbon fiber (PAN-based, T300/T700 classwt %; ≈50–60 vol % for autoclave prepreg laminates50 – 7060
sizing / interlayer toughenerfiber sizing plus thermoplastic toughening particles in aerospace prepregs0 – 21
epoxy resin matrixDGEBA/amine or 180 °C-cure toughened epoxy; substituted by PEEK, BMI, cyanate ester or PA in other variants≥ 30 (balance)

Carbon Fiber Epoxy Matrix — frequently asked

What is Carbon Fiber Epoxy Matrix used for?

Carbon Fiber Epoxy Matrix is typically used for aerospace structural panels, bicycle frames, UAV airframes and booms, robot arms and end effectors, motorsport bodywork and aerodynamic parts and machine tool gantries and idler rollers. In short: lightweight aerospace laminate.

What is the tensile strength of Carbon Fiber Epoxy Matrix?

Carbon Fiber Epoxy Matrix has a typical tensile strength of 650 MPa (94.3 ksi) — stronger than 68% of composite grades. Strength varies by condition: see the 8 listed tempers.

Is Carbon Fiber Epoxy Matrix easy to machine?

Not especially — machinability is rated fair (35/100, better than 50% of composite grades). Use PCD/diamond-coated or diamond-abrasive tooling, high speed and low feed with backing support to avoid delamination and fiber pull-out; vacuum extraction is mandatory (conductive, respirable dust) and coolant/tool wear is the cost driver.

Can Carbon Fiber Epoxy Matrix be welded?

Thermoset CFRP cannot be welded — join by adhesive bonding (peel-ply/abraded surfaces) or bolted joints with generous bearing area; thermoplastic-matrix (PEEK/PA) variants can be induction, resistance or ultrasonically welded.

What surface finishes work on Carbon Fiber Epoxy Matrix?

Cannot be anodized or plated conventionally; finish by resin/gel surfacing film, filler-primer and 2K clear or paint with UV blocker, and always isolate from aluminium/steel with glass-fiber ply or sealant to prevent galvanic corrosion.

Can Carbon Fiber Epoxy Matrix be formed, bent or molded?

Formed by prepreg hand layup/AFP with autoclave or press cure (120–180 °C), RTM/infusion of dry fabric, filament winding, pultrusion, or chopped-prepreg compression molding; thermoplastic tapes are stamp-formed above Tm.

What is the maximum service temperature of Carbon Fiber Epoxy Matrix?

Carbon Fiber Epoxy Matrix is rated for continuous use to about 120°C (248 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

Can FabDigit make parts in Carbon Fiber Epoxy Matrix?

Yes — Carbon Fiber Epoxy Matrix is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.

Sources

  1. CMH-17 Composite Materials Handbook, Vol. 2 (Polymer Matrix Composites — Material Properties)SAE International / CMH-17 (2012)
  2. ASM Handbook Vol. 21: CompositesASM International (2001)
  3. T300 / T700S / M55J carbon fiber and prepreg data sheetsToray Composite Materials (2023)
  4. HexPly 8552 / 913 prepreg and HexTow fiber data sheetsHexcel (2023)
  5. APC-2 / AS4-PEEK thermoplastic tape data sheetSolvay (Cytec) (2022)
  6. Continuous Fiber Reinforcement (CFF/CFR) material propertiesMarkforged (2023)
  7. ASTM D3039 / D6641 / D7264 / D2344 composite test methodsASTM International (2021)
  8. CES / Ashby material property and eco-property data for CFRPAnsys Granta (2022)

Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.