5250-4
5250-4 is a bismaleimide (BMI) prepreg matrix from Cytec/Solvay, offered with IM7 unidirectional and T650 8-harness satin carbon fiber and as neat resin, RTM and PLUS variants.
Reference datasheet — 5250-4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the IM7-UD condition
5250-4 grades and fills
5250-4 is supplied in 5 conditions, soft to hard. IM7-UD is the default FabDigit quotes; the values on this page are for it.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
5250-4 RTM | Use for resin transfer moulding / RFI of dry preforms when prepreg lay-up is impractical. | 60 | 1.7 | 88 Shore D | |
5250-4 neat cast resin | Matrix-only properties for analysis, adhesive/film work and micromechanics input. | 62 | 1.6 | 110 HRM | |
5250-4/T650-35 8-harness satin fabric laminate | Pick the woven-fabric form for drapeable, damage-tolerant skins and complex contours. | 850 | 1.2 | ||
5250-4 PLUS | Choose when impact damage tolerance / CAI and microcrack resistance matter more than peak hot-wet modulus. | 2,700 | 1.7 | ||
IM7-UDDefault 5250-4/IM7 unidirectional tape | Baseline high-stiffness UD tape for primary hot structure and nacelle/inlet skins. | 2,760 | 1.6 |
What is 5250-4?
5250-4 is a bismaleimide (BMI) prepreg matrix from Cytec/Solvay, offered with IM7 unidirectional and T650 8-harness satin carbon fiber and as neat resin, RTM and PLUS variants. It is chosen when structures must run above standard epoxy limits: 218 °C maximum service temperature with 2760 MPa tensile strength, 165 GPa modulus, 1.6 % elongation and 1.58 g/cm³. Costs, cure complexity and a free-standing post-cure step are the trade-offs, along with low machinability (score 30); 8552 epoxy is the lower-temperature, lower-cost alternative. 5250-4 has a density of 1.58 g/cm³ (0.0571 lb/in³), lighter than 54% of composite grades. Its glass-transition temperature is 288°C (550 °F). 5250-4 has a tensile strength of 2,760 MPa (400 ksi), stronger than 79% of composite grades. Elongation at break is 1.6% and the elastic modulus is 165 GPa (23.9 Msi).
What is 5250-4 used for?
- engine nacelles
- high-speed aircraft structures
- radomes
- military aerospace parts
Limitations
- High embodied carbon — 32 kg CO₂/kg, worse than 84% of composite grades
5250-4 properties
Typical room-temperature values for 5250-4-IM7-UD; bars are the position among composite grades.
Physical4
5250-4 has a density of 1.58 g/cm³ (0.0571 lb/in³), lighter than 54% of composite grades. Its glass-transition temperature is 288°C (550 °F).
Mechanical10
5250-4 has a tensile strength of 2,760 MPa (400 ksi), stronger than 79% of composite grades. Elongation at break is 1.6% and the elastic modulus is 165 GPa (23.9 Msi).
Thermal8
5250-4 is rated for continuous service to 218°C (424 °F). It conducts heat at 0.7 W/m·K (0.404 BTU/hr·ft·°F), better than 57% of composite grades. Thermal expansion is 0.3 µm/m·K (0.167 µin/in·°F).
Electrical1
5250-4 has an electrical resistivity of 1×10⁻⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 77% of composite grades. UV resistance is fair.
Sustainability3
Producing a kilogram of 5250-4 takes about 480 MJ of energy and emits 32 kg of CO₂ — more than 81% of composite grades. Typical recycled content is 0%.
Manufacturability2
5250-4's machinability is poor (30/100, worse than 54% of composite grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. 5250-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 5250-4
Is 5250-4 easy to machine?
Trim/drill with PCD or diamond-coated tools, high speed and low feed, backing support and dust extraction; BMI dust is abrasive and requires respiratory protection.
Can 5250-4 be welded?
Not weldable — join by bolting, co-cure/co-bond, or high-temperature adhesive (BMI or polyimide film adhesive) rated for 200 °C+.
Can 5250-4 be formed, bent or molded?
Autoclave cure typically 177 °C at 585–690 kPa with a controlled ramp, then free-standing post-cure to 227 °C for full Tg; slow ramps and thin-ply staging limit exotherm and microcracking.
5250-4 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 |
|---|---|---|
| bismaleimide (4,4'-bismaleimidodiphenylmresin fraction basis | 50 – 70 | 60 |
| o,o'-diallyl bisphenol A (co-reactant)resin fraction basis | 25 – 45 | 35 |
| toughener / thermoplastic + additivesresin fraction basis | 0 – 12 | 5 |
| carbon fiber (IM7 / T650-35)wt % of cured laminate; ~35 wt % resin content in prepreg | 60 – 68 | 65 |
What surface finishes work on 5250-4?
Sand/peel-ply prep then high-temperature primer and topcoat; erosion or metal-mesh lightning-strike layers are commonly co-cured on outer surfaces.
How much does 5250-4 cost?
5250-4 is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
5250-4 — frequently asked
What is 5250-4 used for?
5250-4 is typically used for engine nacelles, high-speed aircraft structures, radomes and military aerospace parts. In short: 218 °C service BMI; above epoxy temperature limits; requires free-standing post-cure.
What is the tensile strength of 5250-4?
5250-4 has a typical tensile strength of 2,760 MPa (400 ksi) — stronger than 79% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is 5250-4 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 54% of composite grades). Trim/drill with PCD or diamond-coated tools, high speed and low feed, backing support and dust extraction; BMI dust is abrasive and requires respiratory protection.
Can 5250-4 be welded?
Not weldable — join by bolting, co-cure/co-bond, or high-temperature adhesive (BMI or polyimide film adhesive) rated for 200 °C+.
What surface finishes work on 5250-4?
Sand/peel-ply prep then high-temperature primer and topcoat; erosion or metal-mesh lightning-strike layers are commonly co-cured on outer surfaces.
Can 5250-4 be formed, bent or molded?
Autoclave cure typically 177 °C at 585–690 kPa with a controlled ramp, then free-standing post-cure to 227 °C for full Tg; slow ramps and thin-ply staging limit exotherm and microcracking.
What is the maximum service temperature of 5250-4?
5250-4 is rated for continuous use to about 218°C (424 °F), and briefly to 260°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 5250-4 cost?
5250-4 is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- CYCOM 5250-4 BMI Prepreg Technical Data Sheet — Solvay Composite Materials (formerly Cytec) (2020)
- CYCOM 5250-4 RTM Resin System Data Sheet — Solvay Composite Materials (2019)
- ASM Handbook Vol.21: Composites — ASM International (2001)
- NCAMP / CMH-17 qualification data for BMI carbon systems — CMH-17 / NIAR (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.