The application of aluminum alloys in automobile lightweighting mainly includes aluminum alloy forgings, metal die castings, aluminum alloy extrusion and drawing products, etc. The specific applications are shown in Table 2.
Table 2 Application of aluminum alloy in automobile lightweight
Cast aluminum alloys are widely used in the current lightweight process of automobiles. They are mainly used in automobile engines, chassis, wheels and other structures. The engine has always been called the "heart" part of automobiles, in the cylinder head, cylinder block, piston The application of aluminum alloy on other parts can not only effectively reduce the overall weight of the engine, but also dissipate the heat generated in the engine's work in time to improve the efficiency of the engine.

Development trend of aluminum alloy in automobile lightweight
The weldability of the aluminum alloy plate is worse than that of the steel during use, which improves the welding performance and welding quality of the aluminum alloy plate and increases the application range of the aluminum alloy. Application of thermoforming technology, superplastic forming technology and electromagnetic conformity forming technology to improve the formability and forming quality of aluminum alloy cover parts.
At present, in addition to the traditional aluminum alloy metal materials, aluminum-based composite materials have been used in the manufacture of lightweight automobiles due to their advantages such as low density, high strength, and high corrosion resistance. Compared with the traditional cast iron piston, the weight of the automobile engine piston is reduced by about 10%, while the heat dissipation is improved by 4 times. Restricted by price and production quality control, aluminum-based composite materials have not yet formed a large scale, but they have shown excellent performance in some automotive parts.

Conclusion
In today's rapid economic and social development, in the face of new energy crises and environmental problems, the lightening of automobiles can effectively improve the fuel efficiency of automobiles, thereby reducing the emission of pollutants. In the process of automobile lightweighting, metal materials such as magnesium alloys and aluminum alloys have been widely used by virtue of their advantages and characteristics. In the future, through technological improvement, the cost of materials will be reduced, the utilization of materials will be improved, and development will be environmentally friendly and possible. Recyclable new materials are also an inevitable trend for lightweight vehicle research and development.