For Al Zn alloy, due to the large solubility of Zn in Al, when the mass fraction of Zn in Al is more than 10%, the strength of the alloy can be significantly improved. Although this kind of alloy has a large natural aging tendency and can obtain high strength without heat treatment, the disadvantages of this kind of alloy are poor corrosion resistance, high density and easy to produce hot cracks during casting. Therefore, this kind of alloy is mainly used to manufacture die casting instrument shell parts.

Aluminum is a silvery white metal, ranking third only after oxygen and silicon in the crust. The density of aluminum is small, only 34.61% of iron and 30.33% of copper, so it is also called light metal. Aluminum is a nonferrous metal whose output and consumption are second only to steel in the world. The density of aluminum is only 2.7103g/cm ³， About 1/3 of the density of steel, copper or brass. Due to its light material, aluminum is often used to manufacture land, sea and air transportation vehicles such as automobiles, trains, subways, ships, aircraft, rockets and airships to reduce self weight and increase loading capacity.