Aluminum is a silvery white light metal. malleable. Commodities are often made into columns, rods, flakes, foils, powders, ribbons and filaments. The melting point is 660°C. The boiling point is 2327°C. The relative density is 2.70, and the density of aluminum liquid is 2.303 g/cm³. Elastic modulus 70Gpa, Poisson's ratio 0.33. The conductivity of aluminum is about 60% of that of copper. If calculated by unit mass, the conductivity of aluminum exceeds that of copper, and it often replaces copper in long-distance transmission. Aluminum is widely used in aviation, construction, automobile, machinery and other industries due to its light weight, good electrical and thermal conductivity, high reflectivity and oxidation resistance.

Aluminum's light weight and corrosion resistance are two outstanding features of its performance.

1. The density of aluminum is very small, only 2.7g/cm³. Although it is relatively soft, it can be made into various aluminum alloys, such as hard aluminum, super hard aluminum, anti-rust aluminum, cast aluminum, etc. These aluminum alloys are widely used in manufacturing industries such as aircraft, automobiles, trains, and ships. In addition, space rockets, space shuttles, and artificial satellites also use a large amount of aluminum and its aluminum alloys.
2. The conductivity of aluminum is second only to silver, copper and gold. Although its conductivity is only 2/3 of that of copper, its density is only 1/3 of that of copper. Therefore, the quality of aluminum wire is only copper wire when transporting the same amount of electricity. half of. The oxide film on the surface of aluminum not only has the ability of corrosion resistance, but also has a certain degree of insulation, so aluminum is widely used in the electrical manufacturing industry, wire and cable industry and radio industry.
3. Aluminum is a good conductor of heat, and its thermal conductivity is three times greater than that of iron. In industry, aluminum can be used to manufacture various heat exchangers, heat dissipation materials and cooking utensils.

4. Aluminum has good ductility (its ductility is second only to gold and silver), and it can be made into aluminum foil thinner than 0.01mm at 100°C to 150°C. These aluminum foils are widely used for packaging cigarettes, candies, etc., and can also be made into aluminum wires and bars, and can be rolled into various aluminum products.
5. The surface of aluminum is not easy to be corroded due to the dense oxide protective film, and is often used to manufacture chemical reactors, medical equipment, refrigeration equipment, petroleum refining equipment, oil and gas pipelines, etc.
6. Aluminum powder has a silver-white luster (generally, the color of metal in powder form is mostly black), and is often used as a coating, commonly known as silver powder and silver paint, to protect iron products from corrosion and to look beautiful.
7. The burning of aluminum in oxygen can emit a lot of heat and dazzling light, which is often used to make explosive mixtures.
8. Thermite is commonly used to smelt refractory metals and weld rails. Aluminum is also used as a deoxidizer in the steelmaking process. Aluminum powder, graphite, titanium dioxide (or oxides of other high-melting point metals) are uniformly mixed in a certain ratio, coated on the metal, and calcined at high temperature to make a high-temperature resistant cermet, which is used in rocket and missile technology. Important application .

9. The reflective performance of aluminum plate to light is also very good, and the reflection of ultraviolet rays is stronger than that of silver. The purer the aluminum, the better its reflective ability, so it is often used to manufacture high-quality reflectors, such as solar cooker reflectors.
10. Aluminum has sound-absorbing properties and good sound effects, so aluminum is also used in broadcasting rooms and ceilings in modern large-scale buildings. Low temperature resistance, when the temperature of aluminum is low, its strength increases instead of brittleness, so it is ideal for low temperature device materials, such as refrigerators, freezers, and production devices for Antarctic snow vehicles.

The birth of aluminum alloy

Pure aluminum has low density, low melting point, and a face-centered cubic structure, so it has high plasticity and is easy to process. It can be made into various profiles and plates, and has good corrosion resistance; but pure aluminum has low strength and is not suitable for structural use. Material. Through long-term production practice and scientific experiments, people have gradually strengthened aluminum by adding alloying elements and using heat treatment, which resulted in a series of aluminum alloys. The alloy formed by adding certain elements can have high strength while maintaining the advantages of pure aluminum such as light weight, so that its "specific strength" (ratio of strength to specific gravity) is better than many alloy steels, and it becomes an ideal structural material. Widely used in machinery manufacturing, transportation machinery, power machinery and aviation industry, etc.Types and applications of aluminum alloys

Types and applications of aluminum alloys

Aluminum alloy has low density, but relatively high strength, which is close to or exceeds high-quality steel. It has good plasticity and can be processed into various profiles. It has excellent electrical conductivity, thermal conductivity and corrosion resistance. It is widely used in industry, and its usage is second only to steel. .
Aluminum alloys are divided into two categories: cast aluminum alloys, which are used in the cast state; deformed aluminum alloys, which can withstand pressure processing and have higher mechanical properties than the cast state. It can be processed into aluminum alloy materials of various shapes and specifications. It is mainly used in the manufacture of aviation equipment, daily necessities, doors and windows for construction, etc.
Deformed aluminum alloys are divided into non-heat-treatable aluminum alloys and heat-treatable aluminum alloys. The non-heat-treatable type cannot improve the mechanical properties through heat treatment, but can only be strengthened through cold deformation. It mainly includes high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum, and anti-rust aluminum. Heat-treatable and strengthened aluminum alloys can improve mechanical properties through heat treatment such as quenching and aging. It can be divided into duralumin, wrought aluminum, super duralumin and special aluminum alloys.

Cast aluminum alloys can be divided into aluminum-silicon alloys, aluminum-copper alloys, aluminum-magnesium alloys, aluminum-zinc alloys and aluminum rare earth alloys according to their chemical composition. Good performance), special aluminum-silicon alloy (heat treatment can be strengthened, high mechanical properties, good casting performance)