Al-Cu-Mg Alloys: 2024 and 7075 Aluminum
Al-Cu-Mg alloys are among the most important heat-treatable aluminum alloy families. The most widely used alloy in this category for aircraft structures is 2024 aluminum. The hardness of 2024-T3 is approximately HB120, while 2024-T4 reaches around HB140.
2024 Aluminum Alloy
2024 aluminum is a copper-based alloy known for its high strength-to-weight ratio and excellent fatigue resistance. Welding is limited to friction welding, and machinability is moderate. Due to its relatively low corrosion resistance, it is typically protected with aluminum or Al-1Zn cladding, although this may slightly reduce fatigue strength.
2024 aluminum is primarily used in high-strength aircraft structures such as fuselages, wings, and belly panels. In addition to its high toughness, it offers stress corrosion and fatigue resistance, making it widely used in civil aircraft, including Boeing and Airbus models. The 2224 aluminum alloy represents a further optimized version of 2024 aluminum.
7075 Aluminum Alloy
7075 is a high-strength, heat-treatable aluminum alloy in the Al-Zn-Mg-Cu system and is considered a predecessor of super-hard aluminum alloys. Common tempers include 7075-T6 and 7075-T73.
7075 aluminum is widely used for structural components, especially in aerospace applications. In the T6 condition (solution treated and artificially aged), 7075 exhibits slightly lower ductility than 2024-T6 but slightly higher than 7A04-T6. The alloy is notch-sensitive under static fatigue but offers better stress corrosion performance than 7A04.
To improve corrosion resistance, 7075 is often overaged. The T73 treatment involves solution treatment followed by two-stage aging: first at a lower temperature, then at a higher temperature. This process reduces tensile strength by roughly 15% but significantly enhances stress corrosion and intergranular corrosion resistance.
GNEE offers both 2024 and 7075 aluminum sheets. Contact GNEE to inquire about specifications and availability.
2024-T4 vs. 7075-T6 Aluminum
Both 2024-T4 and 7075-T6 are high-strength aluminum alloys, but 7075-T6 is considerably stronger due to its zinc content, offering higher tensile and yield strength. This makes it ideal for highly stressed components such as aircraft frames. In contrast, 2024-T4, which is copper-based, provides superior fatigue resistance, toughness, and machinability. It is commonly used for aircraft skins, wing ribs, and rivets, where formability and resistance to cracking are more critical than raw strength.
Key Differences:
Strength: 7075-T6 outperforms 2024-T4 in tensile and yield strength.
Fatigue/Toughness: 2024-T4 excels in fatigue resistance and overall toughness.
Corrosion Resistance: 7075-T6 (Zn-based) is more prone to corrosion than 2024-T4 (Cu-based).
2024-T4 Aluminum
Main Alloying Element: Copper (Cu)
Key Strengths: Excellent fatigue resistance, good fracture toughness, good machinability
Best For: Aircraft skins, wing ribs, and structural components that require high fatigue resistance and good formability
Drawback: Lower strength compared to 7075-T6
7075-T6 Aluminum
Main Alloying Element: Zinc (Zn)
Key Strengths: Very high tensile and yield strength, comparable to some steels
Best For: Highly stressed components such as fuselage frames, landing gear, and structural members requiring maximum strength
Drawbacks: Lower corrosion resistance (especially to exfoliation) and less formable than 2024-T4
GNEE offers both 2024-T4 and 7075-T6 aluminum alloys, providing solutions for aerospace and high-performance structural applications.
