Carbon fiber composites are mainly used in automobiles. Carbon fiber is a new fiber material with high strength and high modulus, and its carbon content is as high as 95%. It is a microcrystalline graphite material made of organic fibers such as flaky graphite microcrystals piled up along the fiber axis and carbonized and graphitized. Carbon fiber is a new material with excellent mechanical properties, and its specific gravity is less than that of steel 1/4. The tensile strength of carbon fiber resin composites is generally above 3500Mpa, which is 7~9 times that of steel, and the tensile elastic modulus is 23000~43000Mpa, which is also higher than steel. Next, let's use Bian Xiao to understand the performance and shortcomings of carbon fiber composites.

Properties of carbon fiber composites

Carbon fiber reinforced composites are different from other FRP composites using traditional fibers (such as glass fiber or aromatic polyamide fiber). Excellent properties of CFRP composites include: light weight. Traditional glass fiber reinforced composites use continuous glass fiber, the content of which is 70% (glass weight/total weight), and the density per cubic inch is usually 0.065 pounds.

Although high-strength CFRP composites are light in weight, compared with glass fiber composites, CFRP composites with unit weight have higher strength and greater hardness. Compared with metal materials, this advantage is more prominent. For example, experience tells us that under the same strength, the weight of CFRP material is only 1/5 of that of steel. It is conceivable why all automobile manufacturers are studying to replace steel with carbon fiber, thus improving the performance of products.

When CFRP composites are compared with aluminum, one of the lightest metals, according to the basic assumption, the weight of aluminum with the same strength is about 1.5 times that of carbon fiber. Of course, there are many other variables in the experiment, which may affect the comparison results. For example, the grade and quality of materials are different, and the composite technology, production technology, fiber structure and quality also need to be taken into account.

Disadvantages of carbon fiber composites

High cost Although CFRP composites have excellent properties, why are carbon fibers not widely used in product production? At present, the production cost of CFRP composites is too high. According to the current market situation (supply and demand), the types of carbon fibers (aviation grade VS commercial grade) and the size of fiber bundles are different, and the prices of fibers are also different. The price per pound of carbon fiber raw materials can reach 5-25 times the price of glass fiber. Compared with steel, the high growth of CFRP materials is more prominent.

Conductivity can be regarded as an advantage of carbon fiber composites, but it may also be a disadvantage in practical application. Carbon fiber is extremely conductive, while glass fiber is insulating. Many products use glass fiber instead of carbon fiber or metal because it requires strict insulation.

In the production of public facilities, many products need to use glass fiber. For example, in the production of ladders, glass fiber is used as the ladder frame, because when the glass fiber ladder is in contact with the power cord, the possibility of electric shock will be much reduced. Carbon fiber ladders are extremely conductive and the consequences are unimaginable.

Although the cost of carbon fiber composites remains high, with the progress of science and technology, more efficient products are just around the corner. Perhaps in our lifetime, we will hopefully witness the wide application of high-performance carbon fiber products in the consumer market, industrial production and automobile manufacturing.