M40J 12K
Grade
GB CCM40J
12K = 12000-filament tow, ~445 g/1000 m
Use the 12K tow (~445 g/1000 m) for more economical large-area lay-up, winding of large cylinders and automated fiber placement; minimum ply thickness is coarser than with 6K.
Values for the 12K condition
Other M40J grades and fills
M40J is listed in 5 conditions; see the grade overview at M40J.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Woven fabric (plain/satin) M40J/epoxy laminate, Vf ≈ 55 % | Choose the plain or satin woven/epoxy laminate (Vf ~ 55 %) for curved shells, reflector panels and quasi-isotropic in-plane stiffness; 0° strength drops to 850 MPa versus unidirectional tape. | — | 850 | 0.9 | — |
Unidirectional M40J/cyanate-ester laminate (space grade), Vf ≈ 60 % | Use the unidirectional cyanate-ester laminate for space hardware: low moisture uptake, low outgassing and 260 °C Tg suit dimensionally stable optical tubes, antenna reflectors and satellite trusses. | — | 2,050 | 0.95 | — |
Unidirectional M40J/epoxy laminate, Vf ≈ 60 %, 0° properties | Pick the 177 °C-cured unidirectional epoxy prepreg laminate (Vf ~ 60 %, 225 GPa at 0°) for high-stiffness trusses, rods and skins; 1 % elongation leaves little damage tolerance. | — | 2,300 | 1 | — |
6000-filament tow, ~225 g/1000 m | Choose the 6K tow (~225 g/1000 m) for thin-ply prepreg, precision fabrics and small-diameter winding where 0.05–0.10 mm ply thickness is required; cost per kilogram is higher than 12K. | — | 4,410 | 1.2 | — |
12KThis page 12000-filament tow, ~445 g/1000 m | Use the 12K tow (~445 g/1000 m) for more economical large-area lay-up, winding of large cylinders and automated fiber placement; minimum ply thickness is coarser than with 6K. | — | 4,410 | 1.2 | — |
What is M40J 12K?
M40J 12K is M40J in the 12K grade — use the 12K tow (~445 g/1000 m) for more economical large-area lay-up, winding of large cylinders and automated fiber placement; minimum ply thickness is coarser than with 6K. M40J 12K has a tensile strength of 4,410 MPa (640 ksi), stronger than 91% of composite grades. Elongation at break is 1.2% and the elastic modulus is 377 GPa (54.7 Msi). M40J 12K has a density of 1.77 g/cm³ (0.0639 lb/in³), heavier than 51% of composite grades.
Advantages
- Stiff — 377 GPa (54.7 Msi), better than 94% of composite grades
- Conducts heat well — 55 W/m·K (31.8 BTU/hr·ft·°F), better than 85% of composite grades
- Good corrosion resistance — 90/100, better than 85% of composite grades
- High service temperature — 400°C (752 °F), better than 78% of composite grades
Limitations
- High embodied carbon — 45 kg CO₂/kg, worse than 90% of composite grades
M40J 12K properties
Typical room-temperature values for M40J 12K; 13 are specific to this condition. Other listed values are M40J reference data and may not represent this condition. Bars are the position among composite grades.
Physical1
M40J 12K has a density of 1.77 g/cm³ (0.0639 lb/in³), heavier than 51% of composite grades.
Mechanical4
M40J 12K has a tensile strength of 4,410 MPa (640 ksi), stronger than 91% of composite grades. Elongation at break is 1.2% and the elastic modulus is 377 GPa (54.7 Msi).
Thermal5
M40J 12K is rated for continuous service to 400°C (752 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), better than 85% of composite grades. Thermal expansion is -0.83 µm/m·K (-0.461 µin/in·°F).
Electrical2
M40J 12K has an electrical resistivity of 9×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 85% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of M40J 12K takes about 650 MJ of energy and emits 45 kg of CO₂ — more than 89% of composite grades. Typical recycled content is 0%.
Manufacturability2
M40J 12K'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 M40J 12K
Is M40J easy to machine?
Cut and drill cured laminates with PCD or diamond-coated tooling at high spindle speed and low feed, with vacuum dust extraction for the conductive dust. Back up drill and router exits with a sacrificial plate to prevent delamination; run dry tow over ceramic guide rollers to avoid fuzzing.
Can M40J be welded?
Not weldable; join with film-epoxy adhesive bonding or mechanical fasteners. Add local reinforcing plies plus titanium or stainless bushings at fastener holes and isolate dissimilar metals to prevent galvanic corrosion.
Can M40J be formed, bent or molded?
Prepreg is autoclave cured at 120–180 °C and 0.3–0.7 MPa, or processed by filament winding and automated fiber placement. The high-modulus fiber restricts minimum bend radius, so keep layups symmetric and balanced to control cure-induced distortion.
What surface finishes work on M40J?
Abrade and apply primer with a polyurethane topcoat for UV and hot/wet protection. Space hardware often uses sprayed coatings or bonded polyimide film to control moisture uptake and thermal-optical properties.
M40J 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 |
|---|---|---|
| sizing (epoxy-compatible)sizing by tow weight; grade suffix indicates sizing type | 0.7 – 1.5 | 1 |
| Nresidual nitrogen | ≤ 0.5 | 0.2 |
| Cgraphitized PAN-based fiber, carbon content | ≥ 99 (balance) | — |
M40J 12K — frequently asked
What is M40J 12K used for?
M40J 12K is typically used for satellite structures, antenna reflectors, aircraft stiffeners and robot arms. In short: high-modulus space-structure fiber; stiffness with usable strength; stiffer than T800 class.
What is the tensile strength of M40J 12K?
M40J 12K has a typical tensile strength of 4,410 MPa (640 ksi) — stronger than 91% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is M40J 12K easy to machine?
Not especially — machinability is rated poor (25/100, worse than 65% of composite grades). Cut and drill cured laminates with PCD or diamond-coated tooling at high spindle speed and low feed, with vacuum dust extraction for the conductive dust. Back up drill and router exits with a sacrificial plate to prevent delamination; run dry tow over ceramic guide rollers to avoid fuzzing.
Can M40J 12K be welded?
Not weldable; join with film-epoxy adhesive bonding or mechanical fasteners. Add local reinforcing plies plus titanium or stainless bushings at fastener holes and isolate dissimilar metals to prevent galvanic corrosion.
What surface finishes work on M40J 12K?
Abrade and apply primer with a polyurethane topcoat for UV and hot/wet protection. Space hardware often uses sprayed coatings or bonded polyimide film to control moisture uptake and thermal-optical properties.
Can M40J 12K be formed, bent or molded?
Prepreg is autoclave cured at 120–180 °C and 0.3–0.7 MPa, or processed by filament winding and automated fiber placement. The high-modulus fiber restricts minimum bend radius, so keep layups symmetric and balanced to control cure-induced distortion.
What is the maximum service temperature of M40J 12K?
M40J 12K 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
- Torayca M40J Technical Data Sheet — Toray Composite Materials (2023)
- ASM Handbook Vol.21: Composites — ASM International (2001)
- CMH-17 (MIL-HDBK-17) Composite Materials Handbook, Vol.2 Polymer Matrix Composites — SAE International (2012)
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.