Properties Of Carbon Fiber

（1）What is Carbon Fiber

The core of carbon fiber is mainly composed of carbon. It is organized by a specialized production process into an extremely strong and lightweight fiber form. This fiber has a very low density, but a high strength, even comparable to some metals. Due to its high specific strength (the ratio of material strength to density). Carbon fiber has inherent advantages in the pursuit of lightweight and high-performance applications.

The manufacturing process of carbon fiber usually involves combining organic fibers. Such as polyacrylonitrile (PAN) or rayon. A series of chemical reactions at high temperatures. To remove the carbon element, leaving a pure carbon structure. This process, known as carbonization, gives carbon fiber exceptional heat resistance. Even under extreme heat conditions. Carbon fiber also retains its original strength and shape. Excellent stability in high temperature environments.

In addition to high strength and heat resistance. Carbon fiber also has a range of other impressive properties. For example, it has excellent anti-friction properties. Making it ideal for applications requiring high frictional resistance. In addition, carbon fiber has good electrical and thermal conductivity. It has broad application prospects in electronic and thermal management. At the same time, carbon fiber also has corrosion resistance. So that it can withstand the erosion of various chemicals.

In the aerospace industry, carbon fiber is widely used to make key components for aircraft, rockets and satellites. Its lightweight and high-strength characteristics allow the spacecraft to reduce weight. Increase payload capacity and achieve greater flight efficiency and performance. In the automotive sector, carbon fiber is used in the body of high-performance cars. And chassis and engine production. The stiffness and mechanical properties of the vehicle are improved, and the overall weight is reduced.

In addition, carbon fiber plays an important role in sports equipment, construction and bridge engineering. In sports equipment, carbon fiber is used to make high-performance items. Like a bike rack. And basketball sticks and tennis rackets. Improve athletes’ competitive performance. In construction and bridge engineering, carbon fiber is used to strengthen and repair aging structures. Improve its compressive and bending strength. Extend its service life.

Carbon fiber composite material is an important direction in the application of carbon fiber. By combining carbon fiber with resin. And other materials such as metals and ceramics. Composites with excellent properties can be produced. These composites inherit the high strength and lightweight properties of carbon fiber. It also incorporates the properties of other materials. Such as good corrosion resistance, wear resistance and impact resistance. This makes carbon fiber composites used in aerospace and automotive, sports equipment. And the application prospect in construction and bridge engineering is broad.

In summary, carbon fiber is a high-performance material. It plays a vital role in various industries. Its unique physical and chemical properties make it ideal for lightweight and high-performance applications. With the continuous development of technology, the application prospect of carbon fiber and its composite materials will be broader.

Code	Weave style	Gram (g/m2)	Yarn		Fiber count 5mm		size(mm)
			Warp yarn	Weft yarn	Warp yarn	Weft yarn
CWP200	plain	200	3k	3k	12.5	12.5	1000
CWP300	plain	300	6k	6k	9.25	9.25	1000
CWT200	twill	200	3k	3k	12.5	12.5	1000
CWT400	twill	400	6k	6k	12.5	12.5	1000
CWU300	Uni-directional	300	12k		9.25		1000

（2）Properties of Carbon Fiber

High Strength and Stiffness:

Carbon fiber possesses exceptional strength and stiffness compared to other materials. It is several times stronger than steel on a weight-to-weight basis.

This high strength-to-weight ratio makes it ideal for applications where weight reduction is critical. Examples include aerospace and automotive engineering.

Lightweight:

Carbon fiber has a very low density, making it extremely lightweight.

Its low weight allows for significant reductions in overall structural weight, improving fuel efficiency and performance in aerospace and automotive applications.

Excellent Thermal Properties:

Carbon fiber has high thermal stability and can withstand extreme temperatures.

It maintains its strength and stiffness even at high temperatures, making it suitable for use in environments with significant heat exposure.

High Chemical Resistance:

Carbon fiber is resistant to a wide range of chemicals, acids, and solvents.

This chemical stability allows it to be used in demanding environments without degrading or corroding.

Good Fatigue Resistance:

Carbon fiber has excellent fatigue resistance. This means it can withstand repeated stress cycles without losing strength or stiffness.

This characteristic makes it suitable for applications that require high durability and longevity. Examples include sports equipment and aircraft parts.

Excellent Electrical Conductivity:

Carbon fiber is an electrical conductor. Can be used in applications where electrical conductivity is required.

Can be used for electrostatic discharge protection. And electromagnetic interference shielding and various electrical components.

Dimensional Stability:

Carbon fiber has low thermal expansion coefficients, meaning it maintains its shape and dimensions even under extreme temperature changes.

This dimensional stability is crucial in precision applications where consistent performance is required.

Design Flexibility:

Carbon fiber can be easily shaped and molded into complex geometries, allowing for high design flexibility.

It can be used to create customized parts and components that meet specific performance requirements.

Durability:

Carbon fiber is highly durable and resistant to wear and tear.

It can withstand repeated impacts and stresses without breaking or fracturing, making it suitable for demanding applications.

Non-Corrosive:

Carbon fiber is non-corrosive and does not rust or degrade over time.

This durability allows it to maintain its performance for extended periods of time, reducing maintenance costs and extending the lifetime of components.

（3）Carbon Fiber is Directionally Dependent

Influence of fiber drawing process:

The manufacturing process of carbon fiber begins with a process of stretching the fiber at high temperatures. In the process. Carbon precursors, such as polyacrylonitrile or asphalt, are stretched at high temperatures to form extremely fine fibers. Due to the action of tensile force. The molecular chains in the fibers are arranged along the stretching direction. Form a highly ordered structure. This directional arrangement makes the carbon fiber have excellent physical properties in the fiber direction.

Due to the orientation of the fibers during the stretching process. Carbon fibers exhibit extremely high strength and modulus in the fiber direction (axial). The directional arrangement of this fiber structure allows the carbon fiber to transfer stress more efficiently when subjected to tensile loads. This results in higher strength and stiffness.

Anisotropy:

The anisotropy of carbon fiber is a direct expression of its directional dependence. Because of the directional arrangement of the fibers. The physical properties of carbon fibers in the fiber direction (such as strength and modulus). And thermal expansion coefficient, etc.) are significantly different from other directions. This anisotropy makes the carbon fiber have different mechanical and thermal properties in different directions.

In practical application. The anisotropy of carbon fiber needs to be fully considered. For example, when designing and manufacturing carbon fiber composites. It is necessary to understand the different properties of carbon fibers in different directions. And according to the specific needs to choose the appropriate fiber orientation and arrangement.

Performance differences:

Carbon fibers have extremely high strength and modulus in the fiber direction (axial). Due to the directional arrangement of the fibers and the highly ordered structure. Carbon fiber can withstand a large tensile load in the axial direction. Not easy to break. This makes carbon fiber widely used in aerospace and automotive. And sports equipment.

However, in the direction perpendicular to the fiber (transverse). The performance of carbon fiber is significantly reduced. Because the connections between the fibers are weak. Carbon fiber is prone to shear failure or interlayer separation in the transverse direction. Therefore. Measures are taken when designing and applying carbon fiber composites. Additional measures are needed to enhance lateral strength and interlayer connections.

Application considerations:

The directional dependence of carbon fiber composites must be fully considered in the design and application. Engineers need to understand how carbon fibers behave differently in different directions. And according to the specific needs to choose the appropriate fiber orientation and arrangement. For example, in aerospace. Engineers optimize the arrangement and layout of carbon fibers based on force analysis and structural requirements. To ensure that the structure maintains sufficient strength and stiffness under complex loads.

Besides. In order to give full play to the performance advantages of carbon fiber. It is also necessary to consider the composite mode and interface properties of carbon fiber with other materials. The composition and preparation technology of carbon fiber composites were optimized. The comprehensive properties of carbon fiber composites can be further improved.

Digital information:

Although there are no direct numbers to quantify the directional dependence of carbon fibers. But by comparing carbon fiber performance data in different directions. This property can be intuitively understood. For example, the axial tensile strength of carbon fiber can often reach thousands of megapascals (MPa). The transverse tensile strength decreased significantly. Similarly, the axial modulus of carbon fiber is much higher than the transverse modulus.

These performance data do not only show the directional dependence of the carbon fiber. It also provides an important reference for its application in different fields. Through reasonable selection and application of carbon fiber composite materials. It can significantly improve the performance and quality of the product.

（4）Key Factors in Determining Properties of Carbon Fiber Composites

There are several key factors to consider when determining the properties of Carbon Fiber Composites (CFCs). The following is a breakdown and summary of these key factors:

 

Types of carbon fiber and resin:

The type of carbon fiber (such as PAN base and asphalt base, etc.) and the type of resin (such as epoxy resin and phenolic resin, etc.) directly affect the performance of the composite material. Different carbon fiber and resin combinations can provide different strength and modulus. As well as heat and corrosion resistance.

Ratio of carbon fiber to resin:

The ratio of carbon fiber to resin (fiber content or fiber volume fraction) determines the density of the composite. Strength and stiffness. Generally speaking. Higher fiber content can improve the strength and stiffness of the composite. But it also increases its brittleness.

Form and orientation of carbon fiber:

Carbon fiber forms (such as unidirectional fibers and fabric fibers). And woven fibers. The properties of the composite are significantly affected by the orientation (fiber lay-up design) and the short cut fiber, etc. For example, unidirectional carbon fiber composites have extremely high strength and stiffness in the fiber direction. However, the performance is poor in the direction perpendicular to the optical fiber.

Quality factors:

Fiber distribution uniformity, voids and other defects can affect the properties of carbon fiber composites. Voids and defects can reduce the mechanical properties and durability of composite materials.

Preparation process:

Preparation processes of carbon fiber composites (e.g. pre-oxidation and carbonization). And graphitization, etc.) have an important impact on the performance of the final product. For example, the temperature of the pre-oxidation process. Time and atmosphere affect the strength of carbon fibers. The temperature distribution and cooling rate during carbonization will affect the microstructure and properties of carbon fibers.

Material defect:

The defects such as pores, inclusions and cracks may be formed during the preparation of carbon fiber reinforced resin matrix composites, which will reduce the mechanical properties and service performance of the composites. The increase of porosity will lead to the decrease of tensile strength.

Effects of temperature and humidity:

In hot and humid conditions. The properties of carbon fiber composites change. The wet state has significant influence on the tensile strength of carbon fiber. But the attenuation of elastic modulus and strain value is not obvious. The infiltration of water will cause the aging of the matrix. The degradation of the interface between fiber and matrix is the main cause of matrix failure.

Digital information:

The tensile strength of carbon fiber resin composites is usually above 3500Mpa. It is seven to nine times that of steel. Its specific strength (the ratio of material strength to density) can reach more than 2000Mpa/(g/cm³). Much higher than A3 steel (about 59Mpa/(g/cm³)). These data directly prove the excellent properties of carbon fiber composites.

To sum up. The properties of carbon fiber composites are affected by many factors. Including the types and proportions of carbon fibers and resins. And morphology and orientation. As well as the preparation process and material defects. And temperature and humidity and so on. In the design and application of carbon fiber composites. These factors must be taken into account. To optimize the properties of composite materials.