Due to its high availability and versatility, aluminum has been used in multiple industries, such as household and industrial appliances.
However, what if we can replace aluminum with another material that is better in every aspect?
Carbon fiber is the “no-brainer” answer to this question.
So what are the advantages and disadvantages of carbon fiber? This article compares carbon fiber vs. aluminum to see how these two prevalent materials contend to become the ultimate choice.
In This Article:
- Is Carbon Fiber Lighter Than Aluminum?
- Carbon Fiber Vs. Aluminum: Which One is Stronger?
- Carbon Fiber Heat Resistance: Better Than Aluminum?
- How Expensive is Carbon Fiber vs. Aluminum?
- Bottom Line: Carbon Fiber Pros and Cons
Carbon Fiber Vs. Aluminum: A Side-by-side Comparison
Is Carbon Fiber Lighter Than Aluminum?
Carbon Fiber Density
Carbon fiber has a density that is nearly half of that of aluminum. With a composition of 30% epoxy resin and 70% fiber, carbon fiber has a density of 1.55 g/cm3, whereas aluminum is 2.7 g/cm3.
Carbon Fiber Weight
As a result, replacing aluminum with carbon fiber in a component of the exact dimensions reduces its weight by approximately 50%.
To put these two materials on a scale, imagine a 1 m2 6 mm thick sheet. An aluminum sheet weighs 16.2 kg, while carbon fiber makes it much lighter at 9.3 kg.
Carbon Fiber Vs. Aluminum: Which One Is Stronger?
Strength at the Same Weight
The strength of a material is characterized by the amount of load it can sustain before it bends or fails. The more significant the resilience, the greater the burden it can hold up.
Weight for weight, a carbon fiber part offers 2 to 5 times more strength, depending on the fiber used, than an aluminum part of the same weight.
To put it in comparison, a 1 m2 carbon fiber sheet that weighs 10 kg will be 7 mm thick, while an aluminum sheet of the same weight will be only 4 mm thick.
Carbon fiber has higher strength at lower density, so a product of the same weight may be thicker, resulting in increased strength from increased thickness alone. For example, increasing the thickness by two times increases the solidity by up to 8 times.
Strength at the Same Thickness
However, when replacing an aluminum part with a carbon fiber part in the same product, engineers tend to keep them the same in all dimensions, meaning the replacement component should not be bigger or thicker than the original one.
This thickness resemblance aims to maintain the component’s compatibility to fit better with other parts of different materials.
A component made of standard carbon fiber of the same thickness as an aluminum one will still provide 60% more strength while weighing nearly half as much.
Carbon fiber strength also performs differently from aluminum. While aluminum permanently bends without returning to its original shape, carbon fiber, despite its lower elasticity, always bounces back after the load is released.
Carbon Fiber Offers Directional Strength
Moreover, carbon fiber exhibits different strength levels in different directions, unlike isotropic metals. Therefore, during the manufacturing process, the order in which the fabrics are woven can enhance the strength in one area while reducing it in others.
Simply put, you can decide which part of the carbon fiber component is more rigid than other areas to suit your needs.
For example, you may want your carbon fiber bike to be more robust in the horizontal and diagonal directions, with components like the crossbar, the downtube, or the chainstay able to withstand more force.
Therefore, carbon fiber used to make these parts can be woven in a different direction to offer more strength and absorb more impact during a ride while staying intact.
Carbon Fiber Heat Resistance: Better Than Aluminum?
Carbon fiber has a low heat conduction measurement as it transfers heat 40 times slower than aluminum. As a result, carbon fiber is an excellent heat insulator.
Carbon fiber has almost no heat expansion (6 times less than aluminum) and is thus widely used in devices such as 3D scanners.
Reinforced carbon fiber can offer impressive heat resistance up to 200 °C (~400 °F). This number is equivalent to aluminum, as the metal loses its strength and becomes very soft at around 200 °C.
However, one advantage of carbon fiber over aluminum is that the composite material does not melt even under extremely high temperatures. In contrast, aluminum has a melting point of 660 °C (1220 °F).
RELATED: Is Carbon Fiber Conductive?
How Expensive Is Carbon Fiber vs. Aluminum?
Carbon fiber cost in comparison to other metals. Source: Infosys
According to a report by Infosys, commercial-grade carbon fiber costs around $30 per kg, while aerospace-grade carbon fiber, which is used on spacecraft and airplanes, may cost a staggering $85 per kg.
Meanwhile, aluminum only costs over $2 per kg, making it one of the cheapest metals on the market.
Carbon fiber is more expensive because it requires more engineering and a more labor-intensive manufacturing process. Aluminum can be manufactured by machine, but carbon fiber is still primarily produced manually.
Furthermore, each frame used to make carbon fiber components needs a customized mold, which adds to the cost. Low production volume due to low commercial demand for carbon fiber up until now also drives up product prices.
Bottom Line: Carbon Fiber Pros and Cons
Carbon fiber is the obvious choice in terms of strength. Even when extra toughness is required, carbon can be combined with other materials to achieve the desired properties.
Carbon fiber continues to be superior in structural design, where less weight can lead to longer life cycles or better performance. Carbon fiber also has a unique sense of aesthetics due to its various finish surfaces, including glossy and matte finishes.
Carbon fiber’s low heat expansion properties are also a significant advantage when creating products that require high precision and stability in temperature-changing environments, such as 3D scanning.
For these reasons, carbon fiber is used to produce luxury items such as watches and wallets. This material distinguishes luxury and ordinary and draws a fine line between style and elegance, allowing it to steal the show in the material market.
However, carbon fiber has almost no elasticity because it does not yield. It may bend slightly under load but not permanently and will not deform. When carbon fiber’s maximum strength is exceeded, it fails suddenly and may shatter into pieces.
Users must keep in mind the non-elastic behavior of carbon fiber when deploying the products to avoid accidents or unwanted damage to carbon fiber.
Carbon fiber parts are also significantly more expensive than aluminum parts due to the high cost of the raw materials, the manufacturing process, and the advanced technology required. However, this cost disadvantage will hopefully be eliminated as production volume increases, and additional production techniques are introduced in the future.
If you have questions about carbon fiber vs. aluminum or any of the details discussed here, connect with us and learn more.
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