IM7 6K
Grade
6K = 6K tow
Choose the 6K tow for thin fabrics, narrow-band winding and high-quality surface plies; unit cost is higher than 12K at the same 5670 MPa strength and 276 GPa modulus.
Values for the 6K condition
Other IM7 grades and fills
IM7 is listed in 8 conditions; see the grade overview at IM7.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
IM7/8552 quasi-isotropic laminate [45/0/-45/90]s | Use the quasi-isotropic [45/0/-45/90]s lay-up values (840 MPa, 60 GPa) for preliminary skin and panel sizing and open-hole strength checks instead of 0°-dominated tape data. | — | 840 | — | — |
IM7/PEEK unidirectional thermoplastic tape | Use the unidirectional PEEK thermoplastic tape when toughness, impact-damage resistance, weldability and in-situ consolidation for automated placement matter; Tg is only 143 °C. | — | 2,600 | — | — |
IM7/5250-4 unidirectional BMI laminate | Pick the bismaleimide unidirectional laminate for continuous service above 200 °C, such as engine nacelles and high-speed airframes; rated to 232 °C with 270 °C Tg but cure is more demanding. | — | 2,620 | 1.6 | — |
IM7/8552 unidirectional epoxy laminate | Pick this 177 °C-cured toughened-epoxy unidirectional prepreg, autoclave-consolidated, as the baseline for primary fuselage and wing skins; 200 °C Tg with a 121 °C service limit. | — | 2,720 | 1.7 | — |
IM7/977-3 unidirectional toughened epoxy laminate | Choose the 977-3 toughened-epoxy unidirectional laminate when higher Tg (215 °C) and better hot/wet retention are needed, giving 150 °C service with 2760 MPa at 0°. | — | 2,760 | 1.7 | — |
24K tow | Use the 24K large tow to cut placement and winding cost on thick-wall structures such as pressure vessels and motor cases; tow tensile strength is slightly lower at 5450 MPa. | — | 5,450 | 1.9 | — |
12K-GPDefault 12K tow, GP sizing | Pick the 12K tow with general-purpose epoxy-compatible sizing as the standard aerospace supply form for prepregging, winding and braiding; listed values are dry-fiber axial, not laminate allowables. | — | 5,670 | 1.9 | — |
6KThis page 6K tow | Choose the 6K tow for thin fabrics, narrow-band winding and high-quality surface plies; unit cost is higher than 12K at the same 5670 MPa strength and 276 GPa modulus. | — | 5,670 | 1.9 | — |
What is IM7 6K?
IM7 6K is IM7 in the 6K grade — choose the 6K tow for thin fabrics, narrow-band winding and high-quality surface plies; unit cost is higher than 12K at the same 5670 MPa strength and 276 GPa modulus. IM7 6K has a tensile strength of 5,670 MPa (822 ksi), stronger than 97% of composite grades. Elongation at break is 1.9% and the elastic modulus is 276 GPa (40 Msi). IM7 6K has a density of 1.78 g/cm³ (0.0643 lb/in³), heavier than 53% of composite grades. 12K-GP is the default condition FabDigit quotes; 6K is available on request or by drawing note.
Advantages
- Good corrosion resistance — 92/100, better than 94% of composite grades
- Stiff — 276 GPa (40 Msi), better than 89% of composite grades
- High service temperature — 400°C (752 °F), better than 78% of composite grades
Limitations
- High embodied carbon — 31 kg CO₂/kg, worse than 83% of composite grades
IM7 6K properties
Typical room-temperature values for IM7 6K; 10 are specific to this condition. Other listed values are IM7 reference data and may not represent this condition. Bars are the position among composite grades.
Physical1
IM7 6K has a density of 1.78 g/cm³ (0.0643 lb/in³), heavier than 53% of composite grades.
Mechanical4
IM7 6K has a tensile strength of 5,670 MPa (822 ksi), stronger than 97% of composite grades. Elongation at break is 1.9% and the elastic modulus is 276 GPa (40 Msi).
Thermal5
IM7 6K is rated for continuous service to 400°C (752 °F). It conducts heat at 5.4 W/m·K (3.12 BTU/hr·ft·°F), better than 66% of composite grades. Thermal expansion is -0.64 µm/m·K (-0.356 µin/in·°F).
Electrical1
IM7 6K has an electrical resistivity of 1.5×10⁻⁵ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 94% of composite grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of IM7 6K takes about 490 MJ of energy and emits 31 kg of CO₂ — more than 83% of composite grades. Typical recycled content is 0%.
Manufacturability2
IM7 6K's machinability is poor (25/100, worse than 65% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with IM7 6K
Is IM7 easy to machine?
Machine cured parts with PCD or diamond-coated tools at high speed and low feed, using vacuum dust extraction and sacrificial backing to prevent delamination. Abrasive waterjet and laser cutting are also commonly used for trimming.
Can IM7 be welded?
The fiber itself is not weldable; only thermoplastic-matrix laminates (PEEK/PEKK) can be resistance-, induction- or ultrasonically welded. Thermoset epoxy and BMI parts must be adhesively bonded or mechanically fastened.
Can IM7 be formed, bent or molded?
Prepreg is hand- or AFP-laid and autoclave cured, typically 177 °C at 0.6 MPa for 8552, or dry fiber is wound or braided and RTM injected. Cured laminates cannot be reshaped.
What surface finishes work on IM7?
Apply primer plus polyurethane topcoat or a gelcoat to resist UV ageing. At aluminium and steel interfaces use fiberglass isolation plies and sealant to prevent galvanic corrosion.
IM7 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.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CPAN-based carbon content | 94 – 96 | 95 |
| Nresidual nitrogen | 3 – 5 | 4 |
| Osurface oxygen functional groups | 0.2 – 1.5 | 0.8 |
| sizing (epoxy-compatible)GP/G sizing content | 0.4 – 1.2 | 0.7 |
IM7 6K — frequently asked
What is IM7 6K used for?
IM7 6K is typically used for military/commercial aircraft structures, UAV airframes and high-performance automotive parts. In short: aerospace baseline structural fiber; high strength, intermediate modulus; broadest qualification database.
What is the tensile strength of IM7 6K?
IM7 6K has a typical tensile strength of 5,670 MPa (822 ksi) — stronger than 97% of composite grades. Strength varies by condition: see the 8 listed tempers.
Is IM7 6K easy to machine?
Not especially — machinability is rated poor (25/100, worse than 65% of composite grades). Machine cured parts with PCD or diamond-coated tools at high speed and low feed, using vacuum dust extraction and sacrificial backing to prevent delamination. Abrasive waterjet and laser cutting are also commonly used for trimming.
Can IM7 6K be welded?
The fiber itself is not weldable; only thermoplastic-matrix laminates (PEEK/PEKK) can be resistance-, induction- or ultrasonically welded. Thermoset epoxy and BMI parts must be adhesively bonded or mechanically fastened.
What surface finishes work on IM7 6K?
Apply primer plus polyurethane topcoat or a gelcoat to resist UV ageing. At aluminium and steel interfaces use fiberglass isolation plies and sealant to prevent galvanic corrosion.
Can IM7 6K be formed, bent or molded?
Prepreg is hand- or AFP-laid and autoclave cured, typically 177 °C at 0.6 MPa for 8552, or dry fiber is wound or braided and RTM injected. Cured laminates cannot be reshaped.
What is the maximum service temperature of IM7 6K?
IM7 6K is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- HexTow IM7 Carbon Fiber Product Data Sheet — Hexcel (2020)
- HexPly 8552 Epoxy Matrix Product Data Sheet — Hexcel (2020)
- NCAMP/NIAR Qualification Material Property Data Report — Hexcel 8552 IM7 Unidirectional Prepreg — NIAR (2011)
- CMH-17 (MIL-HDBK-17) Composite Materials Handbook, Vol. 2 Polymer Matrix Composites — SAE International (2012)
- CYCOM 977-3 / CYCOM 5250-4 Prepreg Technical Data Sheets — Solvay Composite Materials (2019)
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.