CFRP Quasi-Isotropic
A carbon-fiber laminate with similar in-plane properties
Typical values for the temper in the title
A quasi-isotropic laminate is built from unidirectional plies at 0°, ±45° and 90°, so properties are similar in every in-plane direction. This "costs" strength in one direction (about 600 MPa in the database, versus about 1500 for unidirectional), but gives a panel that behaves almost like a metal in-plane, while being much lighter.
It is used for panels and skins, brackets and structural parts loaded from several directions. Through the thickness (out of plane) properties are low, and it is sensitive to delamination on impact.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 600 MPa | |
| Elongation A | 1.2% | |
| Modulus of elasticity E | 55 GPa | |
| Density ρ | 1.55 g/cm³ | |
| Compressive strength | 550 MPa | |
| Interlaminar shear strength (ILSS) | 65 MPa | |
| Machinability | — | relative rating in the site database |
Structure: fiber and matrix
| Feature | Value | Meaning |
|---|---|---|
| Fiber | carbon | |
| Matrix | usually epoxy | |
| Layup | symmetric [0/±45/90] | similar properties in all in-plane directions |
Typical values per producer data.
Constructions and versions
In a composite the "material" is built together with the part: fiber, matrix, ply directions and fiber content are chosen. The same fibers in a different layup give very different properties.
| Version | Properties | When to choose it |
|---|---|---|
| Prepreg and autoclave | maximum quality | aerospace |
| Woven fabric | easy to form complex shapes | formed parts |
| Ready-made plates | standard laminate | parts machined from plate |
Applications
- Panels and skins
- Brackets
- Aerospace and space structural parts
- Drone frames
- Instrument plates
Fabrication
Impact and hidden damage
An impact may cause internal delamination, with no visible mark on the surface. For critical parts, perform nondestructive inspection.
Galvanic corrosion
As with any CFRP: isolate from direct contact with aluminum and steel.
Machining
Drilling and milling with diamond (PCD) or coated carbide tools, with backing to prevent delamination at exit. The dust requires extraction and respiratory protection.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| CFRP UD (Unidirectional Carbon) | 1500 MPa | Not possible | unidirectional CFRP: very strong in one direction · material page |
| 6061-T6 | 310 / 276 MPa | Good — ER4043 | aluminum: isotropic, ductile, heavier · material page |
| GFRP Woven Glass | 350 MPa | Not possible | woven glass fiber: cheaper · material page |
Common mistakes
Assuming it is fully isotropic
Through the thickness properties are much lower.
Ignoring light impacts
Internal damage may be invisible.
Threading directly into the laminate
Joint strength is low. Use bushings and inserts.
Equivalents, standards and supply
| ASTM | D3039 (tensile test) |
|---|---|
| Standards | Test methods: ASTM D3039 / D3410 / D2344 |
| Forms | Prepreg · Layup · RTM |
| Producers | Toray · Hexcel · Solvay Cytec |
Learn more
Values are typical and for comparison only. In composites, properties depend strongly on fiber direction, fiber content, layup and process. For design, rely on data for the specific laminate and tests. The standards mentioned are mainly test methods (ASTM D3039, D3410, D2344 and others). Sources: producer data and the METAL HUB materials database.
Updated: October 31, 2026