Comprehensive analysis of several common aluminum materials

introduction

Aluminum and aluminum alloys have been widely used in modern industry and daily life due to their low density, high strength, good corrosion resistance, excellent processing performance and many other advantages. 6061-T6, 6063, 7075 and 5083 are some of the representative aluminum materials, each of which has unique performance characteristics and is suitable for different application scenarios.

6061-T6 Aluminum

Chemical composition

• The main alloying elements of 6061 aluminum alloy are magnesium (Mg) and silicon (Si), and it also contains a small amount of copper (Cu), manganese (Mn), chromium (Cr) and zinc (Zn). Among them, magnesium and silicon form a strengthening phase Mg₂Si, which plays a key role in improving the strength of the alloy.

Physical properties

• Its density is approximately 2.7g/cm³, and it has good thermal and electrical conductivity, as well as a relatively low coefficient of thermal expansion, which gives it good dimensional stability in environments with large temperature changes.

Mechanical properties

• Strength: In the 6061-T6 state, the tensile strength can reach about 310MPa, and the yield strength is about 276MPa. It has high strength and can withstand a certain load.
• Hardness: The Brinell hardness is usually around 95HB, which can meet the hardness requirements of many mechanical processing and structural applications.
• Toughness: It has good toughness, is not prone to brittle fracture when impacted, and can effectively absorb energy.

Processing characteristics

• Cutting: It has good cutting performance and is easy to process using various conventional cutting processes, such as turning, milling, drilling, etc., and can obtain good surface finish.
• Forming: It can be processed into various shapes of profiles, pipes, bars and plates through forming processes such as extrusion, forging and rolling. During the extrusion process, it has strong deformation ability and can produce products with complex cross-sectional shapes.

Heat treatment process

• T6 heat treatment process includes solution treatment and artificial aging treatment. Solid solution treatment is generally carried out at around 530°C. The alloy is heated to this temperature and maintained for a certain period of time and then quickly cooled so that the alloy elements are fully dissolved into the aluminum matrix. Subsequently, artificial aging treatment is carried out. The aging temperature is about 180°C and the aging time is several hours. Through the aging treatment, the alloy precipitates the strengthening phase, thereby significantly improving the strength and hardness of the alloy.

Corrosion resistance

• 6061-T6 has good general corrosion resistance and can maintain good stability in the atmosphere, fresh water and other environments. The oxide film formed on its surface can play a certain protective role, but in some harsh environments with strong acid, alkali or high salinity, a certain degree of corrosion may occur. The chromium element in the alloy helps to improve its corrosion resistance and make it resist local corrosion, such as pitting, to a certain extent.

Application Areas

• It is widely used in aerospace, automobile manufacturing, mechanical processing, architectural decoration and other fields. In aerospace, it is often used to manufacture aircraft structural parts, landing gear parts, etc.; in the automotive field, it can be used to manufacture body frames, wheels, etc.; in mechanical processing, it is used to manufacture various mechanical parts, tool fixtures, etc.; in architectural decoration, it is often processed into door and window profiles, curtain wall frames, etc.

6063 Aluminum

Chemical composition

• The main alloying elements are magnesium and silicon. Its chemical composition is similar to that of 6061, but the content of each element is slightly different. Relatively speaking, the silicon content in 6063 is slightly higher and the magnesium content is slightly lower.

Physical properties

• The density is also about 2.7g/cm³. It has good thermal conductivity and low thermal expansion coefficient. It has good glossiness and is easy to anodize to obtain a beautiful and corrosion-resistant surface.

Mechanical properties

• Strength: The tensile strength is generally between 200 and 250MPa, and the yield strength is about 180MPa, which is slightly lower than that of 6061-T6.
• Hardness: The Brinell hardness is about 70HB, which is relatively small.
• Toughness: The toughness is good and can meet some application scenarios that do not require particularly high strength but have requirements for formability and appearance.

Processing characteristics

• Extrusion molding: It has excellent extrusion molding performance, can extrude profiles with complex shapes and high dimensional accuracy, and has excellent surface quality. It is one of the main materials for architectural aluminum profiles.
• Machining: It has good cutting performance and can perform drilling, milling, tapping and other processing operations. The surface finish after processing is high.

Heat treatment process

• T5 or T6 heat treatment process is usually used. T5 treatment is to directly air-cool quench after high-temperature extrusion, and then perform artificial aging treatment; T6 treatment is to first perform solid solution treatment and then perform artificial aging treatment. After heat treatment, the strength and hardness of the alloy are improved, while maintaining good toughness and corrosion resistance.

Corrosion resistance

• 6063 aluminum material shows good corrosion resistance in the atmosphere, water and some weak acid and alkali environments. After anodizing, its surface can further enhance its corrosion resistance and form a hard and dense oxide film, which effectively prevents erosion by external media and can be used for a long time in the field of architectural decoration while maintaining a good appearance.

Application fields

• Mainly used in the construction industry, such as building doors and windows, curtain wall frames, decorative strips, etc.; also used to manufacture some furniture accessories, electronic equipment casings and other products with high requirements for appearance and formability.

7075 Aluminum

Chemical composition

• It is a high-strength aluminum alloy, with zinc (Zn), magnesium (Mg) and copper (Cu) as the main alloying elements, and also contains a small amount of chromium (Cr) and other elements. Zinc and magnesium form a strengthening phase, and copper further improves the strength and hardness of the alloy.

Physical properties

• The density is about 2.81g/cm³, the thermal conductivity is good, the thermal expansion coefficient is relatively low, and it can still maintain a certain performance stability under high temperature environment.

Mechanical properties

• Strength: The tensile strength can be as high as 570MPa or more, and the yield strength is about 500MPa. It is the highest strength among several aluminum materials and has extremely high load-bearing capacity.
• Hardness: The Brinell hardness can reach about 150HB, with high hardness and good wear resistance.
• Toughness: Although the strength is high, the toughness is slightly worse than 6061 and 6063. However, under reasonable design and use conditions, it can still meet the requirements of most high-strength applications.

Processing characteristics

• Cutting: Cutting is difficult. Due to its high strength, the wear of the tool is serious. It is necessary to use high-hardness and high-wear-resistant tools, and reasonably select cutting parameters to ensure processing quality and efficiency.
• Forming: It can be formed by forging, rolling and other processes, but due to its large deformation resistance, it has high requirements for processing equipment and processes.

Heat treatment process

• Generally, the T6 heat treatment process is adopted, the solution treatment temperature is about 470℃, and the aging treatment temperature is about 120℃. By precisely controlling the heat treatment process parameters, the best combination of strength and toughness can be obtained.

Corrosion resistance

• The corrosion resistance of 7075 aluminum is relatively weak, especially in an environment containing chloride ions, where stress corrosion cracking is prone to occur. Although its high copper content helps to improve strength, it reduces corrosion resistance to a certain extent. During use, special surface treatment, such as painting, anodizing, etc., is usually required to enhance its corrosion resistance, and it should be avoided as much as possible in environmental conditions that are prone to stress corrosion during design.

Application fields

• It is widely used in the aerospace field, such as aircraft beams, wings, landing gear and other key structural components; in the military industry, it is used to manufacture parts for weapons and equipment; in the field of high-end sports equipment, such as bicycle frames and golf club heads, its high strength and lightweight characteristics are used to improve product performance.

5083 Aluminum

Chemical composition

• The main alloying element is magnesium, and it also contains a small amount of manganese (Mn) and other elements. The high content of magnesium gives the alloy good corrosion resistance and strength.

Physical properties

• The density is about 2.66g/cm³, which is relatively low among these aluminum materials. It has good thermal conductivity and electrical conductivity, and a moderate thermal expansion coefficient.

Mechanical properties

• Strength: The tensile strength can reach about 315MPa, and the yield strength is about 230MPa. The strength is high and can withstand large tensile and bending loads.
• Hardness: The Brinell hardness is about 90HB, and the hardness can meet the general engineering application requirements.
• Toughness: It has excellent toughness, especially in low temperature environment, it can still maintain good toughness, and it is not easy to brittle fracture. It is suitable for some occasions that require low temperature performance.

Processing characteristics

• Welding performance: The welding performance is excellent, and a variety of welding methods (such as arc welding, resistance welding, etc.) can be used for welding. The welded joint has high strength and good weld quality. It is widely used in the manufacture of welded structural parts.
• Cutting: Good cutting performance, easy to process into parts of various shapes.

Heat treatment process

• Usually no heat treatment is performed to strengthen, and strength is improved by work hardening. During cold working, such as cold rolling and cold drawing, the strength of the alloy will gradually increase while maintaining a certain plasticity and toughness.

Corrosion resistance

• 5083 aluminum has excellent corrosion resistance, especially in marine environments and media containing chloride ions. The composition of its alloy elements enables it to form a stable oxide film on its surface, effectively resisting the erosion of seawater, salt water, etc., and is an ideal material for shipbuilding, marine engineering and other fields. Even when exposed to harsh marine environments for a long time, it can maintain good structural integrity and performance stability.

Application fields

• Mainly used in shipbuilding, marine engineering, pressure vessels, refrigeration equipment and other fields. In shipbuilding, it is used to manufacture hull structures, decks, bulkheads, etc.; in marine engineering, it can be used to manufacture offshore platforms, submarine pipelines, etc.; in the field of pressure vessels, due to its good corrosion resistance and welding performance, it can be used to manufacture containers for storing various liquids or gases; in refrigeration equipment, its low-temperature toughness and corrosion resistance are used to manufacture refrigerated truck bodies, cold storage wall panels, etc.

Conclusion

The four aluminum materials 6061-T6, 6063, 7075 and 5083 have obvious differences in chemical composition, physical properties, mechanical properties, processing characteristics, heat treatment process, corrosion resistance and application fields. In actual engineering applications, it is necessary to comprehensively consider and select appropriate aluminum materials based on specific use requirements, such as strength, hardness, toughness, corrosion resistance, processing difficulty, cost and other factors. Only in this way can the advantages of aluminum materials be fully utilized to meet the needs of different fields and engineering projects and promote the development and progress of related industries. Whether in the high-tech field of aerospace or in ordinary industries such as building decoration and daily necessities manufacturing, these aluminum materials play an irreplaceable and important role. With the continuous development of materials science and technology, their performance will be further optimized and expanded, and their application prospects will be broader.