Carbon fiber itself is a brittle material, but why can it improve the toughness of composite materials?

Carbon fiber itself is indeed a relatively brittle material, but it is used as a reinforcing material in composite materials. However, due to its advantages, it can improve the toughness of composite materials. Below, Xiaokong will introduce the improvement methods and processes for everyone~

1、 Features that can improve resilience:

1. High strength: Carbon fiber has high tensile strength and stiffness, and its strength is higher than many common materials such as steel and aluminum. Therefore, when carbon fiber is combined with other materials, it can increase the overall strength of the composite material.

2. Lightweight: Carbon fiber has a lower density compared to metal materials such as steel and aluminum. Therefore, the use of carbon fiber can reduce the weight of composite materials, making them more suitable for applications that require lightweighting.

3. High specific strength and high specific stiffness: Carbon fiber has the characteristics of high specific strength and high specific stiffness, that is, the strength and stiffness are very high compared to the density of the material. This characteristic enables carbon fiber to effectively increase toughness and durability in composite materials.

4. Corrosion resistance: Carbon fiber has good corrosion resistance and can better maintain its performance in some harsh environmental conditions compared to metal materials. This is very important for applications that require long-term use and high corrosion resistance.

The composite of carbon fiber and bamboo simplifies the production process of multi curved products made from carbon fiber materials and reduces processing costs.

2、 Improvement methods

1. Energy absorption: Carbon fiber has the characteristics of high strength and stiffness, which can absorb and disperse the energy brought by external loading, thereby slowing down the transmission of stress. This means that when composite materials are subjected to impact or stress, carbon fibers can bear most of the load and prevent crack propagation, thereby improving the toughness of the composite material.

2. High displacement to failure: The high displacement of carbon fibers in composite materials to failure characteristics also helps to improve toughness. Compared to other fiber-reinforced materials such as glass fiber, carbon fiber has higher strain capacity and can withstand greater deformation without rapid failure. This enables carbon fiber composite materials to better absorb impacts and withstand dynamic loads.

3. Preventing crack propagation: Carbon fiber has excellent toughness and can effectively resist crack propagation. Its high strength and stiffness can prevent rapid propagation of cracks in the material, thereby improving the crack resistance of composite materials.

4. Interface strength: The surface of carbon fiber is usually improved by special surface treatment and coating to enhance the interface bonding with the substrate material. Good interface bonding can increase the adhesion between carbon fibers and matrix materials, further improving the toughness of composite materials.

3、 Improve the process

1. Directional arrangement: In the preparation of composite materials, the arrangement direction of carbon fibers can be controlled through orientation and stacking. Carbon fibers are usually oriented and arranged according to design requirements to bear the maximum load in the material. By precisely controlling the orientation of carbon fibers, the toughness of composite materials can be improved in specific loading directions.

2. Pre stressing treatment: The carbon fibers in carbon fiber composite materials can be subjected to a certain tension during the pre stressing process, causing them to stretch and be fixed in a specific state in advance. This treatment can improve the toughness and fatigue performance of composite materials, enabling them to better resist crack propagation under stress loading.

3. Interface modification: In composite materials, the interface between carbon fibers and matrix materials plays a crucial role. By using interface modification technology, the adhesion between carbon fiber and matrix material can be increased, improving the strength and durability of the interface. This helps prevent crack propagation at the interface, thereby improving the toughness of the composite material.

4. Damage monitoring and repair: Damage in carbon fiber composite materials can significantly affect their toughness and performance. Therefore, the use of damage monitoring technology can detect cracks and damages in a timely manner and take repair measures. This can delay and prevent the propagation of cracks, improving the toughness of composite materials.