component

Matrix material: It is a continuous phase in composite materials, which plays a role in bonding and fixing reinforcement materials, while transferring external loads to the reinforcement materials. Common matrix materials include polymers (such as epoxy resin, polyester resin, etc.), metals (such as aluminum, magnesium, etc.), and ceramics (such as aluminum oxide, silicon nitride, etc.). For example, in composite materials based on epoxy resin, epoxy resin can stick other materials together like glue and transmit force to other reinforcing materials when subjected to external forces.

Reinforcement material: It is a dispersed phase in composite materials, mainly used to improve the mechanical properties of materials, such as strength, stiffness, and toughness. Reinforcing materials can be fibers (such as carbon fiber, glass fiber, aramid fiber, etc.), particles (such as silicon carbide particles, alumina particles, etc.), or thin sheets (such as mica sheets, metal sheets, etc.). Taking carbon fiber as an example, it has high strength and modulus. Adding carbon fiber to the matrix material, just like adding steel bars to concrete, can greatly improve the strength of composite materials.

Performance characteristics

Higher specific strength and specific modulus: The ratio of the strength and modulus (the ratio of stress to strain of a material under stress) of composite materials to their density, i.e. specific strength and specific modulus, is often higher than that of traditional materials. This gives them a significant advantage in fields where material weight is strictly limited, such as aerospace. For example, the specific strength of carbon fiber reinforced composite materials is several times that of steel, which means that using carbon fiber composite materials can greatly reduce the weight of the structure under the same strength requirements, thereby improving fuel efficiency or payload.

Strong designability: Materials with specific properties can be designed based on specific application requirements by selecting different matrix materials, reinforcement materials, their ratios, and composite material forming methods. For example, if a material with high toughness and corrosion resistance is needed, suitable polymer matrix and fiber-reinforced materials can be selected, and their ratios can be determined to meet performance requirements.

Good fatigue resistance: Many composite materials exhibit excellent fatigue resistance during repeated loading and unloading processes. For example, when fiber-reinforced composite materials are subjected to alternating stress, fibers can prevent crack propagation, allowing the material to withstand more fatigue cycles. This characteristic makes composite materials widely used in structures that can withstand dynamic loads, such as the blades of wind turbines.

Forming method

Hand lay up molding: This is a relatively simple molding method. Lay the reinforcing material (such as fiberglass fabric) on the mold, and then manually apply the matrix material (such as resin) onto the reinforcing material to fully saturate it. After curing, the composite material product is obtained. This method is suitable for making products with complex shapes and large sizes, such as the hulls of small yachts and partial prototypes of car bodies. However, the quality of hand molded products is greatly affected by the technical level of the operators, and the production efficiency is relatively low.

Compression molding: Pre mixed composite materials (containing matrix material and reinforcement material) are placed in a mold and molded at a certain temperature and pressure. This method can produce products with high dimensional accuracy and good surface quality, such as electrical casings, automotive components, etc. The production efficiency of compression molding is relatively high, but the mold cost is also relatively high.

Spiral forming: mainly used for manufacturing composite material products with a rotating body shape. Immerse continuous reinforcing fibers (such as carbon fibers) in a matrix material (such as resin), and then wrap them around a core mold according to a certain pattern. After curing, the product is obtained. This method is commonly used for manufacturing pipelines, containers, rocket engine casings, etc. For example, in the manufacture of high-pressure gas containers, winding molding can distribute fibers in the optimal direction of force, improving the strength of the container.