People always asked about the difference between carbon fiber and aluminum . Why carbon fiber is expensive than aluminum ? Hopefully below information helps you to understand .
Weight : The density of carbon fiber composites is about 1.6 g/cm³, which is significantly lighter than aluminum (density is about 2.7 g/cm³), about 40-50% lighter.
Strength : The tensile strength of carbon fiber can reach 7,000 MPa, while aluminum alloys are usually between 90 and 700 MPa. For example, the tensile strength of 7075 aluminum alloy is about 572 MPa.
Stiffness : The elastic modulus of carbon fiber ranges from 200 to 700 GPa, compared to 69 to 79 GPa for aluminum alloys, which means carbon fiber provides superior stiffness and reduced bending in high-performance applications.
Heat resistance : Aluminum has a thermal conductivity of about 205 W/m·K, which is better at dissipating heat than general-purpose carbon fiber (5-10 W/m·K). However, carbon fiber can withstand higher temperatures without degrading, while aluminum melts at about 660°C.
Corrosion resistance : Carbon fiber itself is highly resistant to corrosion, but the resin matrix used may degrade if not protected. Aluminum forms a protective oxide layer that provides good corrosion resistance, but may still corrode in acid or alkaline environments.
Cost comparison : Carbon fiber is expensive due to its superior performance, with commercial-grade carbon fiber prices ranging from $30 to $85 per kilogram, and aerospace-grade carbon fiber costs between $85 and $90 . In contrast, aluminum is more economical, costing just over $2 per kilogram .
Ease of manufacturing : The production process of carbon fiber is complex and time-consuming, involving multiple steps such as precursor production, oxidation and carbonization. Aluminum is easier to manufacture, through processes such as casting, extrusion and rolling, which are highly automated and efficient.
Comparison of application fields for carbon fiber and metal aluminum
Aerospace : Carbon fiber benefits aircraft components such as fuselages, wings and tails due to its lightweight properties. Its excellent strength-to-weight ratio and corrosion resistance make it indispensable in the aerospace industry.
Automotive Industry : High-performance vehicles, including racing cars and luxury sports cars, use carbon fiber to reduce weight and improve acceleration, braking and fuel efficiency. Aluminum is widely used in the automotive field for engine blocks, wheels, chassis components and body panels.
Bicycles and Sports Equipment : Carbon fiber is a popular choice for high-end bicycles, golf clubs, tennis rackets and other sports equipment, where its light weight and high strength-to-weight ratio provide significant performance advantages to athletes. Aluminum is also used in the manufacture of bicycles and various sports equipment, especially in mid-range products where cost is a factor.
Medical and Manufacturing : Carbon fibers are used in the medical field for lightweight, strong devices such as prosthetics, wheelchairs, and surgical instruments. Aluminum is also prevalent in medical and manufacturing applications, where its lightweight and corrosion-resistant properties make it suitable for medical devices.
Consumer Electronics : Aluminum is preferred for housings and heat sinks in consumer electronics. Its excellent thermal conductivity helps dissipate the heat generated by electronic components, ensuring the life and performance of the device.
