It is popular and simple to say that a composite material is a material in which two or more different materials are physically or chemically mixed into one substance. Like concrete is the most common composite material in life.

Most people may have imagined that the composite material is a plastic composite such as FRP. In fact, composite materials are divided into metal and non-metal. Metal is also commonly called alloy (such as aluminum alloy); non-metal is usually made of resin, rubber, ceramic, graphite, carbon, etc., using glass fiber, carbon fiber, boron fiber, aramid silicon carbide, asbestos fiber, etc. There are whiskers, wires and hard fine particles to make reinforcing materials. The reason why composite materials are compounded is to make a mutual synergy effect in various materials, so that the comprehensive performance of composite materials is far greater than the various single raw materials that make up composite materials. This is one of the important reasons why materials such as FRP are  popular.

Among the composite materials, fiber reinforced materials are the most widely used and the largest amount. It is characterized by a small specific gravity, a large specific strength and a specific modulus. For example, carbon fiber and epoxy resin composite materials, its specific strength and specific modulus are several times larger than steel and aluminum alloy, but also has excellent chemical stability, friction and wear resistance, self-lubrication, heat resistance, fatigue resistance, Resistance to creep, noise reduction, electrical insulation and other properties. The graphite fiber is compounded with a resin to obtain a material having a coefficient of expansion almost equal to zero. Another feature of fiber reinforced materials is the anisotropy, so the fiber arrangement can be designed according to the strength requirements of different parts of the part. Aluminum-based composites reinforced with carbon fiber and silicon carbide fibers maintain sufficient strength and modulus at 500 °C. Silicon carbide fiber is compounded with titanium, which not only improves the heat resistance of titanium, but also is resistant to wear and can be used as an engine fan blade. Silicon carbide fiber and ceramic composite, recycled resin composite resin-based composite material: Resin-based composite material is a composite material made of glass fiber, carbon fiber, aramid fiber and the like as a matrix.

The three most common composite materials are described in detail below.

The glass fibers currently used for high-performance composite materials mainly include high-strength glass fibers,  quartz glass fibers, and high silica glass fibers. It is cost-effective, so it has maintained a growth rate of 10% to meet the needs of the vast industrial sector. High-strength fiberglass composites are currently widely used in military and civilian products. Militaryly used to make bulletproof helmets and bulletproof suits, as well as helicopter wings. Various high-pressure pressure vessels, civilian aircraft straight, sporting goods, various high-temperature resistant products, and recently reported tire cords with excellent performance. Up to now, the three composite materials of high-strength glass fiber, quartz glass fiber and high-silica glass fiber have been widely used in China. Among them, high-strength fiberglass frp has been in the international leading position, with independent intellectual property rights and small-scale industries. The annual output is about 500 tons. It is expected to continue to climb in the future.

Since the 1980s, the Netherlands, Japan, and the former Soviet Union have also carried out research and development work on aramid fiber. At present, aramid fiber is mainly used in aerospace products, and it is not widely used in civilian applications except for parts of automobiles. It is worth mentioning that the specific strength of ultra-high molecular weight polyethylene fibers ranks first among various fibers, especially its chemical resistance and anti-aging properties. It also has excellent high frequency sonar permeability and seawater corrosion resistance. Therefore, the application prospects are also very good. Thermosetting Resin Composites and Thermoplastic Composites: Thermosetting resin-based composites are based on thermosetting resins such as unsaturated polyester resins, epoxy resins, phenolic resins, vinyl ester resins, etc., with glass fibers, carbon fibers, and aramid fibers. A super high molecular weight polyethylene fiber or the like is a composite material made of a reinforcing material. Thermoplastic resin-based composites mainly include long fiber reinforced pellets (LFP), continuous fiber reinforced prepreg (MITT), and glass fiber mat reinforced thermoplastic composites (GMT). Because these two composites have a long history of development, they are not as well known as common resin composites.