M55J vs T300
Composite · grade comparison
M55J and T300 are both composite grades. M55J is the stronger of the two: tensile strength 4,020 MPa (583 ksi) against 3,530 MPa (512 ksi) for T300, about 14% more. In exchange, T300 is the more ductile: elongation 1.5% versus 0.8% for M55J. T300 is lighter (1.76 g/cm³ vs 1.91 g/cm³ for M55J) and M55J is stiffer (540 GPa vs 230 GPa).
M55JChoose it when strength drives the design, or when the part sees heat.
T300Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
M55J vs T300: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Shear Strength
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Min Service Temperature -269°C-452 °F · Max Service Temperature (short-term) 500°C932 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 92 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 700 L/kg83.9 gal/lb · Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | M55J | T300 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
M55J vs T300 — frequently asked
Is M55J stronger than T300?
Yes. M55J has a typical tensile strength of 4,020 MPa (583 ksi) against 3,530 MPa (512 ksi) for T300 — about 14% more.
Which is cheaper, M55J or T300?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, M55J or T300?
T300, by a small margin. Both rate poor for machinability — 25/100 against 18/100 for M55J.
Ready to make it?
Upload a CAD file and FabDigit prices the part in M55J and T300 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.