Aluminum and aluminum alloys are one of the most widely used and economical materials. Since the beginning of 1956, the world's aluminum production has been the largest in the world. At present, the output and dosage of aluminum (in tons) is second only to steel and the second largest metal for human applications. Moreover, aluminum is rich in resources. According to preliminary calculations, the storage of aluminum accounts for more than 8% of the constituents of the earth's crust.
Aluminum's light weight, high specific strength and corrosion resistance are outstanding features.
The density of aluminum is very small, only 2.7 g/cm
Although it is relatively soft, it can be made into various aluminum alloys such as hard aluminum, super-hard aluminum, rust-proof aluminum, cast aluminum, and the like. These aluminum alloys are widely used in the manufacturing industries of airplanes, automobiles, trains, and ships. In addition, a large number of aluminum and its aluminum alloys are used in space rockets, space shuttles, and satellites. For example, a supersonic large aircraft consists of approximately 70% aluminum and its aluminum alloy. Aluminum is also used extensively in the construction of ships, and the amount of aluminum used in a large passenger ship often reaches several thousand tons.
High specific strength of aluminum alloy
The tensile strength of high-strength aluminum alloy in 7XXX alloy can reach 700MPa or more, while the weight of aluminum alloy is only about 1/3 of steel, and the equivalent weight is equivalent to the tensile strength of steel above 2100MPa.
Good corrosion resistance
Aluminum is a very active metal, but it is very stable in a general oxidizing environment. This is aluminum which forms an oxide film on the surface of aluminum in oxygen, small and other oxidants. The aluminum oxide film not only has strong corrosion resistance, but also has certain insulation properties.
Aluminum is second only to silver, copper and gold
Although its conductivity is only 2/3 of that of copper, the density is only 1/3 of that of copper, so the same amount of electricity is delivered. The quality of the aluminum wire is only half that of the copper wire. Therefore, aluminum has a wide range of uses in the electrical appliance manufacturing industry, the wire and cable industry, and the radio industry.
Aluminum is a good conductor of heat
Its thermal conductivity is 3 times larger than that of iron and 10 times that of stainless steel. Aluminum can be used in the manufacture of various heat exchangers, heat-dissipating materials and cookware.
Aluminum has good ductility
Its ductility is second only to gold and silver, and it can be made into aluminum foil thinner than 0.006 mm. These aluminum foils are widely used for packaging cigarettes, candy, etc., and can also be made into aluminum wire, aluminum strips, extruded into various shaped materials, and can roll various aluminum products. Aluminum can be cut, drilled and welded in the usual way.
Aluminum powder has a silvery white luster
Generally, the color of the metal in the powder is mostly black, which is commonly used as a coating, commonly known as silver powder and silver paint, to protect the iron product from corrosion and aesthetics.
Burning in oxygen can give off heat and dazzling light
Commonly used in the manufacture of explosive mixtures, such as ammonium-aluminum explosives (mixed with ammonium nitrate, charcoal powder, aluminum powder, soot and other combustible organics), combustion mixtures (such as bombs and shells made of aluminothermic agents can be used to attack difficult Fire target or tank, cannon, etc.) and lighting mixture (eg 68% cerium nitrate, 28% aluminum powder, 4% shellac).
Aluminothermic agents are commonly used to smelt refractory metals and welded rails
Aluminum is also used as a deoxidizer in steel making. Aluminum powder and graphite, titanium dioxide (or other high melting point metal oxide) are uniformly mixed at a certain ratio, coated on metal, and calcined at high temperature to form high temperature resistant cermet. It has important applications in rocket and missile technology.
The aluminum plate also has good reflection properties against light and heat.
Reflected ultraviolet light is stronger than silver. The purer the aluminum, the better its reflection ability. Therefore, it is often used to make high-quality mirrors, such as solar cooker mirrors, and can be used as thermal insulation materials.
Aluminum is not magnetic
It does not create an additional magnetic field and does not interfere in precision instruments.
Aluminum has sound absorbing properties and sound effects are also good
Therefore, aluminum is also used in the broadcasting room and the ceiling of a modern large-scale building.
Aluminum low temperature resistance
When aluminum is low in temperature, its strength is increased without brittleness, so it is ideal for use in cryogenic equipment such as refrigerators, freezers, Antarctic snowmobiles, and hydrogen oxide production units. At the same time, the low-temperature resistance of aluminum is small, the resistance of aluminum is lower than that of high-purity copper and silver below 50K, and the aluminum becomes a superconductor when it is below 1.2K.
