Composite material refers to the material made of two or more materials with different restrictions through special processing, which is called composite material. It consists of two parts: matrix and reinforcement. Such as glass fiber reinforced plastics, carbon fiber reinforced composites and the like.

The matrix materials of composite materials can be divided into two categories: metal and nonmetal. Commonly used metal substrates are aluminum, magnesium, copper, titanium and their alloys. Non-metallic matrix mainly includes synthetic resin, rubber, ceramics, graphite, carbon and so on.

Among metallic materials, ferrous metals are also called steel materials, including industrial pure iron containing more than 90% iron, cast iron containing 2% ~ 4% carbon, carbon steel containing less than 2% carbon, and various structural steels, stainless steels, heat-resistant steels, high-temperature alloy stainless steels and precision alloys.