Among the composite materials, fiber reinforced materials are the most widely used and the largest amount. It is characterized by small specific gravity, large specific strength and specific modulus. For example, the composite material of carbon fiber and epoxy resin, its specific strength and specific modulus are several times larger than those of steel and aluminum alloy, and it also has excellent chemical stability, anti-friction and wear resistance, self-lubricating, heat resistance, fatigue resistance, resistance Creep, noise reduction, electrical insulation and other properties. The composite of graphite fiber and resin can obtain a material with an expansion coefficient almost equal to zero. Another feature of fiber reinforced materials is anisotropy, so the arrangement of fibers can be designed according to the strength requirements of different parts of the product. The aluminum matrix composites reinforced with carbon fibers and silicon carbide fibers can still 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 has wear resistance, and can be used as engine fan blades. Silicon carbide fiber and ceramic composite, the service temperature can reach 1500 ℃, which is much higher than the service temperature of super alloy turbine blades (1100 ℃). Carbon fiber reinforced carbon, graphite fiber reinforced carbon or graphite fiber reinforced graphite, constitute ablation resistant materials, which have been used in spacecraft, rocket missiles and atomic energy reactors. Due to their low density, non-metal matrix composites can reduce weight, increase speed and save energy in automobiles and aircraft. Composite leaf springs made from a mix of carbon and glass fibers have stiffness and load-carrying capacity comparable to steel leaf springs that are more than 5 times heavier