Aluminum Alloy

What Is Aluminum Alloy？

Aluminum alloy is an alloy based on aluminum and a certain amount of other alloying elements, and it is one of the light metal materials. Primary aluminum is collectively referred to as electrolytic aluminum in the market supply, which is the raw material for the production of aluminum and aluminum alloy materials. Aluminum is a metal with low strength and good plasticity. Except for some pure aluminum, it is made into alloy in order to improve the strength or comprehensive performance. Adding an alloying element to aluminum can change its structure and performance, making it suitable for various processing materials or casting parts. Commonly added alloying elements include copper, magnesium, zinc, and silicon. In addition to the general characteristics of aluminum, aluminum alloys also have specific characteristics of alloys due to the different types and quantities of added alloying elements. The density of aluminum alloy is 2.63～2.85g/cm, it has high strength (σb is 110～650MPa), the specific strength is close to that of high alloy steel, the specific stiffness is higher than that of steel, it has good casting performance and plastic processing performance, and good electrical conductivity. , Thermal conductivity, good corrosion resistance and weldability, can be used as structural materials, has a wide range of applications in aerospace, aviation, transportation, construction, electromechanical, light and daily necessities.

The Classification Of Aluminum And Aluminum Alloy Use

More common grades: 1060, 2024, 5052, 6061, 6063, 7075.

• 1060: 1060 belongs to ordinary industrial pure aluminum, with an aluminum content of not less than 99.60%. It is characterized by low strength and work hardening is the only way to strengthen. Good thermal and cold working performance, high thermal conductivity and excellent corrosion resistance. It is widely used in industrial equipment that requires good formability, corrosion resistance and solderability, and can also be used as an electrical conductor material.
• 2024: The composition and structure of 2024 alloy are the same as that of 2A12 alloy, except that the content of impurities Fe and Si in 2124 alloy is lower. 2024 alloy thin plates, thick plates and profiles have been successfully used in the manufacture of aircraft and rocket skins, cabin sections, integral fuel tank wall panels, wing beams, etc.
  The magnesium content of 5052: 5052 alloy is 2.5%, which is the lower magnesium content among aluminum-magnesium rust-proof aluminum. It is widely used in the manufacture of aircraft fuel and fuel pipes and fuel tanks, various parts of ships and transportation vehicles, sheet metal products, instruments, street lamp brackets, rivets and wires, etc.
• 6061: 6061 alloy is Al-Mg-Si series heat-treatable and strengthened aluminum alloy, which can be processed into plates, tubes, rods, shapes, wires and forgings. Widely used in building profiles, large structural parts that require good corrosion resistance, trucks, ships, railway vehicle structural parts, pipes, homes, etc.
• 6063: 6063 alloy is Al-Mg-Si series heat-treatable and strengthened aluminum alloy, which can be extruded into bars, profiles, and tubes. It is widely used in building structural materials and decorative materials, such as door frames, window frames, wall panels, containers, furniture, elevators, and decorative components of different colors such as airplanes, ships, light industry departments, and buildings.
• 7075: 7075 alloy is Al-Zn-Mg-Cu super-hard aluminum, which is characterized by good plasticity after solution treatment and obvious heat treatment strengthening. It can be processed into plates (with or without aluminum), pipes, profiles, bars and forgings. Mainly used for aircraft structural parts and other high-strength corrosion-resistant structural parts.

The Grades Of Aluminum Alloy

•  – Nomenclature of the grades of pure aluminum: when the aluminum content is not less than 99.00%, it is pure aluminum, and its grades are represented by the 1XXX series. The last two digits of the grade indicate the minimum aluminum percentage. When the minimum aluminum content is accurate to 0.01%, the last two digits of the grade are the two decimal places in the minimum aluminum content. The second letter of the grade indicates the modification of the original pure aluminum. If the second letter is A, it is expressed as original pure aluminum; if it is other letters from B to Y (selected in the alphabetical order according to international regulations), it is expressed as a modification of the original pure aluminum, which is the same as the original pure aluminum. In comparison, its element content is slightly changed.
•  – Nomenclature of aluminum alloy grades: Aluminum alloy grades are represented by 2XXX~8XXX series. The last two digits of the grade have no special meaning and are only used to distinguish different aluminum alloys in the same group. The second letter of the grade indicates the modification of the original alloy. If the second letter of the grade is A, it is expressed as the original alloy; if it is other letters from B to Y (selected in the order of the alphabet in international regulations), it is expressed as a modified alloy of the original alloy.

The Composition Classification Of Aluminum Alloy

Aluminum alloys are divided into deformed aluminum alloys and cast aluminum alloys according to their composition and processing methods. Wrought aluminum alloy is made by first melting and casting alloy ingredients into billets, and then plastic deformation processing, through rolling, extrusion, stretching, forging and other methods to produce various plastic processing products. Casting aluminum alloy is a blank that is directly cast into various parts using sand molds, iron molds, investment molds, and die-casting methods after smelting ingredients.

1. Deformed aluminum alloy

Deformed aluminum alloys are semi-finished aluminum alloys such as tubes, rods, wires, and shapes made by various pressure processing methods. According to its use, it can be divided into 5 categories: anti-corrosion aluminum alloy, super duralumin, special aluminum, duralumin, and forged aluminum.

The main alloying elements in commonly used anti-rust aluminum alloys are manganese and magnesium. Adding manganese can increase its corrosion resistance, adding magnesium to strengthen it and reduce its specific gravity. It is characterized by corrosion resistance, good polishing, and can maintain a bright surface for a long time. The strength is higher than that of pure aluminum, and it is mostly used to make parts, pipes, daily necessities, decorations, etc. that are in contact with liquids; Duralumin, also known as duralumin, is an alloy of aluminum, copper, and magnesium, and contains a small amount of manganese. Copper and magnesium are more soluble in aluminum and have a strengthening effect, while manganese makes them corrosion resistant. Duralumin can be used to manufacture rivets, aircraft propellers and high-strength parts on aircrafts according to the content of its alloying elements; super-duralumin is duralumin containing zinc, its hardness and strength are higher than duralumin, and different varieties of super-duralumin It is used to manufacture various structural parts and high-load parts. It is one of the important materials in the aviation industry; Forged aluminum has high plasticity and high strength in general conditions, and is used to manufacture various forgings or stamping parts, such as internal combustion engine pistons, etc.; Special aluminum is used under specific conditions, with different components, each has its own purpose.

2. Cast aluminum alloy

Cast aluminum alloy is an aluminum alloy used to directly cast various shapes of mechanical parts. According to the different main elements added, it can be divided into Al-Si series alloy, Al-Zn series alloy and Al-Mg series alloy. Each system has its own brand and is more complicated.

3. Difference

The fundamental difference between wrought aluminum alloy and cast aluminum alloy can be illustrated by the phase diagram of aluminum-based binary alloy: the alloy with the composition located to the left of point B′ belongs to the wrought aluminum alloy. When heated to a temperature higher than the solid solution line (BD), it A single-phase α solid solution can be obtained, which has good plastic processing performance and is suitable for cold and hot pressure processing. Due to the development of fusion casting technology, the composition of some deformed aluminum alloys has been expanded to point F. Alloys whose composition is to the right of point E are cast aluminum alloys. Because its structure contains low-melting eutectic, it has good fluidity, can prevent hot cracking, and is suitable for casting. It can be seen that the composition content of cast aluminum alloy is higher than that of deformed aluminum alloy. Aluminum alloys are divided into two types: heat-treatable and non-heat-treatable. The alloy whose composition is to the left of point D, the composition of its solid solution does not change with the change of temperature, there is no phase change during heat treatment, and no strengthening occurs, which is called non-heat treatment strengthened alloy; the alloy with alloy composition between DF, its solid solution The composition changes with temperature, that is, there is a phase change during heat treatment, and thus strengthened, which is called heat-treatable strengthened alloy.

The Development History Of Aluminum Alloy

The initial stage of aluminum alloy research and development was mainly related to the aviation industry. It only has a history of nearly a hundred years. However, it has developed rapidly and its scope of use has continued to expand. Among metal materials, its output ranks second after steel. Ranked first among metal materials. Aluminium alloy will have great development: adopt newer process methods, improve the original alloy, develop new alloy, give newer and more perfect performance, expand the scope of use, and increase the amount of use.

• In 1908, Alcoa invented the electrical aluminum alloy 1050 and made it into a steel core aluminum stranded wire, creating a pioneer in high-voltage remote power transmission.
• In 1915, Alcoa invented the 2017 alloy and in 1933 invented the 2024 alloy, which enabled the rapid expansion of the application of aluminum in aircraft. In 1933, Alcoa invented 6061 alloy and then created the extruder quenching process, which significantly expanded the application range of extruded profiles.
• In 1943, Alcoa invented 6063 alloy and 7075 alloy, opening a new era of high-strength aluminum alloys.
• In 1965, Alcoa invented the A356 cast aluminum alloy, which is a classic cast aluminum alloy.

With the in-depth research on aluminum alloy materials, the use of high-strength aluminum alloys (2000 and 7000 series) in commercial aircraft with their excellent comprehensive performance has reached more than 80% of their structural quality, and has therefore been recognized by the global aviation industry. General attention. Aluminum alloy began to be gradually used in life, military, and technology.

The Application Of Aluminum Alloy

Aluminum alloy has the characteristics of low density, good mechanical properties, good processing properties, non-toxic, easy to recycle, electrical conductivity, heat transfer and corrosion resistance, etc., used in the marine industry, chemical industry, aerospace, metal packaging, transportation, etc. Widely used in the field.

1. Aerospace

Aluminum alloy is the main material used in the manufacture of aircraft. Compared with the mild steel used in automobile manufacturing, aluminum alloy is expensive and has a low density. The relative density is 2.8. Compared with the relative density of mild steel of 7.8, it is about one-third lighter. Although the strength is similar, it is the material for airplanes. Lightness is the most important thing, and it has strong corrosion resistance and convenient processing. Therefore, aluminum alloy is the most ideal material for making airplanes.

Duralumin can be used to manufacture rivets, aircraft propellers and high-strength parts on aircrafts according to the content of its alloying elements; super-duralumin is duralumin containing zinc, its hardness and strength are higher than duralumin, and different varieties of super-duralumin It is used to manufacture various structural parts and high-load parts. It is one of the important materials in the aviation industry.

2. Marine industry

Aluminum and aluminum alloys are used more and more widely in the shipbuilding industry, ranging from small motorboats to 10,000-ton tankers, from offshore hovercraft to submarine submarines, from civilian to military, from fishing vessels to marine mining vessels, all with excellent comprehensive performance. The aluminum alloy produces ship shells, support structures, supporting facilities, pipelines, etc.

Aluminum alloy used in the marine industry can reduce the overall weight of the ship, increase the speed of the ship, and resist the corrosion of the ship by seawater.

The aluminum alloys used in the marine industry are mainly aluminum-copper alloys, aluminum-magnesium alloys and aluminum-silicon alloys. Aluminum-copper alloy is widely used in ships in my country and Russia, but its poor seawater corrosion resistance hinders its development in the shipbuilding industry. Aluminum-magnesium alloys are mainly used for hull shells, water pump pipes, pump shells and frame brackets, etc. The grades are 5083, 5086, 5456, 5466, etc. The aluminum-silicon alloy has moderate structural strength, good fluidity, and strong filling ability. It is easy to produce components with high density and complex structure, such as high-pressure valves, cylinder blocks, pumps, gearbox casings, turbine blades, etc.

3. Application in the chemical industry

Aluminum has good thermal conductivity. Aluminum and aluminum alloys are widely used in the production of heat exchange equipment in chemical equipment, storage tanks resistant to concentrated nitric acid corrosion, adsorption filters, fractionation towers, pipelines and many linings. Cast aluminum alloy has good fluidity, strong mold filling ability, small shrinkage rate, not easy to form cracks, good corrosion resistance (a protective film of aluminum oxide and silicon dioxide can be formed on the surface), light weight, good mechanical properties, It is widely used in the manufacture of corrosion-resistant parts with complex structures, such as cylinders, pipe fittings, valves, pumps, pistons, etc. Aluminum has many special uses in chemical production. Aluminum does not produce sparks, aluminum alloy can produce containers that contain easily volatile substances; aluminum is non-toxic, will not cause food deterioration, does not affect the appearance of goods, and does not corrode goods. Therefore, aluminum alloys are widely used in the production of food and chemical industries. equipment.

4. Application in the metal packaging industry

Aluminum alloy can be used for metal packaging. It has the following excellent characteristics: good mechanical properties, light weight, high compressive strength, durable, easy to store and transport goods; good barrier properties, can prevent damage to goods from sunlight, oxygen and humid environments , Can extend the shelf life of items; good texture and aesthetics, aluminum alloy used for packaging has a unique metallic luster, good touch, beautiful, and improve product quality; non-toxic and easy to recycle, can be recycled, save resources, and reduce environmental pollution. Aluminum alloy is widely used in beer, beverage and other food cans, mostly in stamping and drawing forming structures. Aluminum foil utensils are beautiful, light in weight, and good in heat transfer. They are used for fast food packaging. They have the functions of preservation, taste preservation and non-toxicity, and are used by more and more food industries. The aluminum alloy metal hose can be squeezed and deformed, and the contents can be used after squeezing. It is simple and convenient. It is often used for cream cosmetic packaging.

5. Application in other industries

Aluminum alloy has high specific strength, light weight, good fluidity, strong filling ability, good corrosion resistance, and low melting point. It is widely used in tractors, locomotive parts, electronic products, medical equipment, architectural decoration and other industries. Aluminum alloy has excellent ductility and is widely used in the daily necessities industry and the food industry. In the field of power transmission, wires made of aluminum alloy are low in cost, light in weight, good in corrosion resistance, heat transfer, easy to conduct electricity, and wear resistance, so people are paying more and more attention. In the field of power transmission, aluminum alloy is used the most, and up to 90% of high-voltage wire materials are aluminum products [10]. Aluminum-silicon alloy can be used as a good deoxidizer to reduce the sensitivity of steel to produce subcutaneous bubbles, steel-making deoxidation improves the quality of steel, the market for aluminum-silicon alloy is large, and the national annual demand reaches one million tons.