Every morning when we wake up from our sleep and start a day of life and work, there is always something like an old friend who accompanies us all day, that is, aluminum, which has been integrated into our lives, and it is everywhere.
Aluminum is the most abundant metal element in the earth’s crust. Aluminum is an aluminum alloy made by adding other metals to the main material. It has many excellent properties, such as lightness, environmental protection, and corrosion resistance. Known as aluminum has good recycling characteristics, about 70% of the aluminum produced 100 years ago is still serving human beings
In the development and utilization of new energy, aluminum is indispensable. Products manufactured by aluminum and aluminum alloys through casting, forging, extrusion and calendering are widely used. The proportion of aluminum is only one-third of that of steel. , Industrial aluminum extrusion materials and aluminum rolled materials are gradually replacing steel as the basic material in the field of transportation and construction.
From high-speed rail cars to ships, from military to civilian, the use of aluminum alloys is increasing, and the weight of a spacecraft entering space orbit is reduced by 1 kilogram, and its launch cost will be saved by more than 100,000 yuan.
Energy saving and weight loss are calculated in grams in the aerospace field. The aerospace field has become an important application market for aluminum alloy materials. Automotive engines, wheels, car bodies, high-speed rail bodies, mechanical equipment and electrical equipment, and daily necessities are all made of aluminum alloy. In order to meet the requirements of light weight.
In ancient times, humans began to make pottery with clay containing aluminum. However, because aluminum has a weak oxidation property, it is difficult to extract it. Therefore, it has more reserves on the earth than other metals, but it uses significantly more than copper. Metals such as iron are much later.
In 1825, German chemists refined gray metal aluminum with low purity.
In 1854, French chemists successfully used sodium as a reducing agent to successfully make metal aluminum ingots. After that, aluminum became an expensive material, and products made of aluminum could only be enjoyed by the emperor and nobles.
In 1884, other metals were added to aluminum to make aluminum alloy materials, and the first application was in construction.
In 1908, the American company invented the electrical aluminum alloy, which is characterized by high hardness and high copper content, and is applied to high-voltage transmission lines.
Later, casting aluminum alloys and high-strength aluminum alloys were invented one after another, and its application range was continuously expanding.
Aluminum alloy is a general term for alloys with aluminum as the main material. The main alloy elements are copper, silicon, magnesium, zinc, etc. Aluminum alloy has the advantages of corrosion resistance, easy processing, high strength and small density.
Aluminum alloy has corrosion resistance, which is impossible for many metals. Because the aluminum alloy surface has a hard film, this layer of film covers the aluminum alloy surface to isolate the aluminum alloy from oxygen. With time, this The film will continue to thicken. If this film is damaged, it will re-grow a protective film to make its aluminum products have good corrosion resistance. Of course, it also needs a later surface treatment to make the aluminum alloy more resistant to corrosion.
Many people think that aluminum will not oxidize. In fact, there are no absolutely non-oxidizing metals in the world, only the conditions and degrees are different. Aluminum alloys will also oxidize if the surface protective film is damaged.
The shortcomings of aluminum alloy are also obvious, that is too brittle. Now scientists have developed a new type of aluminum alloy material. This shortcoming of aluminum alloy is being changed. By introducing “faults” in the crystal structure of the metal, it can be greatly improved Material strength, except that the strength of the new aluminum alloy material is similar to that of stainless steel, this feature can also be used for corrosion-resistant coatings.
From the microscopic layer, the metal is composed of crystalline atoms that are stacked repeatedly. When a layer is missing, it will be collapsed and broken. The interesting thing is that these stacked faults can actually make the material strength become Higher, this feature is introduced into the new aluminum material, while increasing the strength and ductility of the material, it also improves its thermal stability, and the new product is expected to be applied to the corrosion-resistant coating of 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 used more.
The extrusion process is to heat the aluminum alloy rod to about 400 ℃, and apply pressure to one end of the heated aluminum alloy rod in the extruder, and the other end is the corresponding shape of the mold, the aluminum alloy will become aluminum after cooling from the mold For alloy products, this process is like squeezing toothpaste. Different openings determine the shape of the toothpaste. The extruded aluminum alloy products are mainly used as building profiles.
The die casting process is to press the aluminum alloy solution into the mold cavity to make a casting. The aluminum alloy solution is first put into the press chamber, then the injection punch advances, and the aluminum alloy melt pressure is injected into the cavity.
After the aluminum alloy melt is solidified, the die-casting mold is opened, and the casting is taken out. The die-cast aluminum alloy product has high precision and good quality, and is mainly used for parts on cars, airplanes, and ships.
Although aluminum alloy has good oxidation resistance, in order to better reflect product quality, enhance use and visual effects, aluminum alloy will also do various surface treatments, mainly including polishing, wire drawing, electroplating, sandblasting, etc. to further improve aluminum The decorative and protective properties of the alloy.
Today, people are increasingly demanding low-carbon environmental protection, aluminum alloy has become a substitute for many metals, its low density, high strength, easy processing and other advantages, more and more applications in automobiles, high-speed rail, aviation, ships The wider it is, the aluminum alloy will definitely make a greater contribution to human development.
