Aluminium vs Carbon fibre
Aluminium and Carbon fibre are genuine alternatives to one another — a choice somebody actually makes — and differ on 2 measured properties, density most clearly.
Aluminium vs Carbon fibre
These are different kinds of thing (element, material). Fewer properties mean the same thing across both, so a like-for-like reading may not be available.
Aluminium
Al
The most abundant metal in the Earth's crust, and until the 1880s more valuable than gold because nobody could extract it cheaply.
Carbon fibre
Filaments of near-pure carbon with extraordinary stiffness-to-weight, used in composites rather than alone.
| Property | Aluminium | Carbon fibre |
|---|---|---|
| Atomic number Only one of the two has a figure we can stand behind, so there is nothing to compare. | 13 | Not known |
| Density | 2.7 g/cm³ higher | 1.75–1.95 g/cm³ |
| Electrical conductivity Only one of the two has a figure we can stand behind, so there is nothing to compare. | 37.7 MS/m | Not known |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | 660.32 °C | Not known |
| Mohs hardness Only one of the two has a figure we can stand behind, so there is nothing to compare. | about 2.75 | Not known |
| Molar mass Only one of the two has a figure we can stand behind, so there is nothing to compare. | 26.982 g/mol | Not known |
| Tensile strength One of these is a directional measurement (along the fibre axis) and the other is not. The comparison holds only in that direction. | 70–130 MPa | 3500–7000 MPa higher |
| Thermal conductivity Only one of the two has a figure we can stand behind, so there is nothing to compare. | 237 W/(m·K) | Not known |
Choosing between them
Carbon fibre is recorded as a substitute for Aluminium — lighter, stronger.
What it gives up: Anisotropic, invisible when damaged, and an order of magnitude more expensive — it fails without denting first, which is the property an inspector relies on in metal.
In this application, on the evidence cited above.