Aluminum is the most abundant metal element in the earth’s crust. Aluminum as the main material is added to other metals to make aluminum alloy, which has many excellent properties such as lightness, environmental protection, corrosion resistance, etc., providing us with all kinds of convenience, and aluminum, which has the name of green metal, has good recycling characteristics, and about 70% of aluminum produced a hundred years ago is still serving mankind today.
In the development and utilization of new energy, aluminum is indispensable. Products made of aluminum and aluminum alloy through casting, forging, extrusion and calendering are widely used, and the proportion of aluminum is only one-third of steel.
From high-speed railway carriages to ships, from military to civilian, the use of aluminum alloy is increasing.
Energy saving and weight reduction are calculated in grams in the aerospace field. The aerospace field has become an important application market for aluminum alloy materials, and automobile engines, wheels, bodies, high-speed railway bodies, mechanical equipment and electric power equipment, as well as daily commodities, are all made of aluminum alloy to achieve the requirement of light weight.
In ancient times man began to use clay containing aluminum to make pottery, but because of the weak oxidation properties of aluminum, it was difficult to refine it out, so it was more abundant than other metals on earth, but used significantly later than copper, iron and other metals.
In 1825, German chemists refined gray metal aluminum with low purity.
In 1854, French chemists used sodium as a reducing agent and succeeded in making metallic aluminum ingot blocks. In the period after this, aluminum became an expensive material and products made of aluminum were only available to the emperor and nobility.
In 1884, other metals were added to aluminum to make aluminum alloys, which were first used in construction.
In 1908, the American company invented electrical aluminum alloy, which is characterized by high hardness and high copper content, and was used in high-voltage transmission lines.
Later on, casting aluminum alloy and high strength aluminum alloy were invented one after another, and its application range was expanded continuously.
Aluminum alloy is the general name of the alloy with aluminum as the main material, and the main alloy elements are copper, silicon, magnesium, zinc, etc. Aluminum alloy has the advantages of corrosion resistance, easy processing, high strength and low density.
Aluminum alloy has corrosion resistance, which many metals can not do, because there is a layer of hard film on the surface of aluminum alloy, which covers the surface of aluminum alloy, making it isolated from oxygen. Of course, it also needs the later surface treatment to make the aluminum alloy more corrosion resistant.
Many people think that aluminum will not be oxidized, in fact, there is no metal in the world that is absolutely not oxidized, but the conditions and degree are different.
The disadvantage of aluminum alloy is obvious, that is, it is too brittle, now scientists have researched a new aluminum alloy material, this disadvantage of aluminum alloy is being changed, by introducing “fault” in the crystal structure of the metal, it can greatly enhance the strength of the material, in addition to making the strength of the new aluminum alloy material is similar to stainless steel, this feature is also This property can be used for corrosion-resistant coatings.
Microscopically speaking, metal is composed of layers of repeatedly stacked crystal atoms, and when a layer is missing, the stack will collapse and fracture. The new product is expected to have applications in corrosion-resistant coatings for electronic equipment and vehicles.
Aluminum alloy has so many advantages, how is it processed into various aluminum alloy products? Nowadays, the extrusion process and die-casting process are more frequently used.
The extrusion process is to heat the aluminum alloy bar to about 400℃, and by applying pressure to one end of the heated aluminum alloy bar in the extrusion machine, the other end is the corresponding shape of the die, the aluminum alloy will become aluminum alloy products after cooling out from the die, this process is like squeezing toothpaste, different openings determine the shape of the extruded toothpaste, the extruded aluminum alloy products are mainly used as construction profiles.
The die casting process is to press the aluminum alloy solution into the mold cavity to make the casting. The aluminum alloy solution is first put into the press chamber, and then the pressure injection punch advances to melt and press the aluminum alloy into the cavity.
After the molten aluminum alloy solidifies, the die-casting mold is opened and the casting is taken out. The die-cast aluminum alloy products have high precision and good quality and are mainly used for parts on automobiles, aircraft and ships.
Although aluminum alloy has very good resistance to oxidation, in order to better reflect the product quality and enhance the use and visual effect, aluminum alloy will also do various surface treatments, mainly polishing, brushing, electroplating, sandblasting, etc. to further improve the decorative and protective properties of aluminum alloy.
With the increasing demand for low carbon and environmental protection, aluminum alloy has become a substitute for many metals. With its low density, high strength, easy processing and other advantages, it is used more and more widely in the fields of automobile, high speed rail, aviation, ship and so on.