2000 Aluminum VS. 7000 Aluminum Alloy

2000 series aluminum alloys: This series of aluminum alloys respond well to heat treatment (such as solution treatment, aging treatment, etc.). Through appropriate heat treatment processes, the strength of 2000 series aluminum alloys can be significantly improved. However, its aging hardening process is usually slow and it takes a long time to reach optimal performance.

7000 series aluminum alloys: 7000 series aluminum alloys are more sensitive to heat treatment, especially through the T6 heat treatment state, which can achieve high strength. This alloy has a fast heat treatment speed and can achieve a significant increase in strength in a short period. It is usually more suitable for industrial needs that require rapid mass production.

2000 series aluminum alloys: 2000 series alloys have excellent fatigue strength, which makes them very suitable for use in structural parts that are subjected to repeated loads, especially in the aviation field. For example, 2024 alloy is often used in aircraft parts that need to withstand variable loads for a long time.

7000 series aluminum alloy: Although the static strength (tensile strength, yield strength) of the 7000 series is higher than that of the 2000 series, its fatigue strength is relatively low, especially in harsh environments. It is more sensitive to the extension of fatigue cracks, so some special structures may need to be strengthened to prevent fatigue failure.

2000 series aluminum alloy: The density of the 2000 series aluminum alloy is about 2.78 g/cm³, which is slightly higher than that of conventional pure aluminum (about 2.7 g/cm³). Although its density does not change much, its strength-to-weight ratio (strength-to-weight ratio) is still relatively good, which is suitable for applications that need to reduce weight but have high strength requirements.

7000 series aluminum alloy: The density of the 7000 series is slightly higher, usually around 2.85–2.9 g/cm³. Despite the slight increase in density, due to its extremely high strength, the 7000 series still has advantages in high-strength, lightweight design, especially in aerospace and high-performance sports equipment.

2000 Series Aluminum Alloys: The weldability of the 2000 series is poor, especially alloys with a high copper content. Cracks and defects are easily generated during welding, so special attention needs to be paid to the welding process, or other connection methods (such as riveting, bolting, etc.) are used.

7000 Series Aluminum Alloys: The weldability of the 7000 series aluminum alloys is also difficult, especially alloys with a high zinc content such as 7075, due to the tendency to thermal cracks. After welding, the mechanical properties of the material may also decrease, so mechanical connections or precision machining are often preferred rather than welding in high-strength applications.

2000 Series Aluminum Alloys: The thermal expansion coefficient of the 2000 series is relatively small, usually about 22.8 µm/m°C. This makes it have better dimensional stability in environments with large temperature fluctuations.

7000 Series Aluminum Alloys: The thermal expansion coefficient of the 7000 series aluminum alloy is higher, about 24 µm/m°C. In high-temperature environments, its dimensional changes may be greater than those of the 2000 series, which needs to be considered in the design.

2000 series aluminum alloy: The ductility of 2000 series aluminum alloy is generally better than that of 7000 series, especially when it is not strengthened. It can be deformed more at a lower temperature and is not easy to crack during processing, so it is suitable for manufacturing parts with complex shapes.

7000 series aluminum alloy: The ductility of 7000 series aluminum alloy is relatively poor, especially in high high-strength state. Although this problem can be improved by appropriate processing technology, its use is limited in applications requiring large deformation.

2000 series aluminum alloy: The resistance of 2000 series aluminum alloy to stress corrosion cracking is generally poor, especially in high humidity or corrosive environments. Stress corrosion cracking is more likely to occur. To reduce such problems, it is usually necessary to treat it with anodizing or anti-corrosion coating.

7000 series aluminum alloy: The 7000 series aluminum alloy is very sensitive to stress corrosion cracking, especially in high-strength states (such as 7075-T6). Some new 7000 series alloys have improved stress corrosion resistance by adjusting the alloy element ratio and heat treatment process, such as newer alloys such as 7475.