From the endless flow of cars running on the road to the street lamp post, aluminum die casting parts can be found everywhere. In the die casting industry, aluminum casting and aluminum alloy casting are confusing. What’s the difference between them?

Aluminum vs Aluminum Alloy: Compare Characteristics and Properties

Aluminum is a very light metal with a density of 2.7 g/cm³. Aluminum has good thermal conductivity and conductivity. When the section and length of aluminum are the same as that of copper, the conductivity of aluminum is about 61% of that of copper. Aluminum has good resistance to atmospheric decay because it is easy to form a dense alumina film on its surface, which can prevent the further oxidation of internal metals. Aluminum basically does not react with concentrated nitric acid and organic acids. Industrial pure aluminum has high plasticity and is easy to withstand various molding processes, but its strength is too low. Therefore, pure aluminum can only be used as structural material after its strength is improved by cold deformation strengthening or alloying. Aluminum is a non-magnetic material with good reflection performance, which can reflect both visible light and ultraviolet light. The impurities in aluminum are silicon and iron. When the impurity content is higher, its conductivity, corrosion resistance, and plasticity are lower

If an appropriate amount of some alloy elements are added to aluminum, and then after cold processing or heat treatment, some characteristics can be greatly improved. The most commonly used alloy elements in aluminum are copper, magnesium, silicon, manganese, and zinc. Sometimes these elements are added alone or together. In addition to the above elements, sometimes trace amounts of titanium and chromium are added. According to the composition and production process characteristics of aluminum alloy, it can be divided into cast aluminum alloy and deformed aluminum alloy. Wrought aluminum alloys are usually made into plates, pipes, bars, and various profiles through hot or cold pressure processing, i.e. rolling, extrusion, and other processes. This kind of alloy requires high plasticity, so the alloy content is less. Casting aluminum alloy is to directly pour liquid metal into a sand mold to make various parts with complex shapes. This kind of alloy is required to have good castability, that is, good fluidity. When the alloy content is small, it is suitable to be used as a deformed aluminum alloy. When the alloy content is large, it is suitable to be used as cast aluminum alloy. The elastic modulus of aluminum alloy is small, which is only equivalent to 1/3 of steel, that is, under the same section and the same load, the elastic deformation of aluminum alloy is three times that of steel, the bearing capacity is not strong, but the seismic performance is good. The tensile strength of the aluminum alloy is much lower than that of steel. Aluminum alloy has a low melting point and excellent plasticity at room temperature and high temperature. It can be extruded into structural parts with extremely complex section shapes, thin wall, and high dimensional accuracy. Aluminum alloy not only has appropriate mechanical properties but also has excellent corrosion resistance, thermal conductivity, and polishing properties.

In the casting process, pure aluminum has poor fluidity, good thermal conductivity, high melting point and good oxidation resistance. Die cast aluminum has strong fluidity, high plasticity, low melting point, and easy surface treatment.

Pure Aluminum Die Casting vs Aluminum Alloy Die Casting

The main material of aluminum die casting is pure aluminum, which has high purity. First, the pure aluminum material is heated at a high temperature to make it liquid, and then it is poured into the mold of the die casting machine. After the casting process, the aluminum casting part is formed with a limited shape. Aluminum is widely used in the die casting industry because of its good fluidity and plasticity and good metal texture.


The main materials of aluminum alloy die casting are aluminum alloy. Compared with pure aluminum die casting, the purity of aluminum alloy is not so high, but the hardness is stronger than pure aluminum die casting. Aluminum alloy die casting has a wider range and high dimensional accuracy. After the die casting is formed, it needs polishing treatment. In this way, the aluminum alloy die casting has good smoothness and gloss. Aluminum alloy die casting is generally used in consumer, electronics, automobile, communication, home, instrument, and other industries. Compared with pure aluminum die casting, the performance of aluminum alloy is better, and the supply chain and technology are more mature. It is an important part of mechanical parts.