7050 aluminum alloy is a high-strength, heat-treatable wrought alloy primarily used in aerospace applications. It belongs to the 7xxx series, which are alloyed with zinc as the primary alloying element, along with magnesium and copper, to achieve exceptional strength levels.
Key Characteristics
7050 aluminum plate is renowned for its:
- High Mechanical Strength: It offers one of the highest strength-to-weight ratios among aluminum alloys, making it ideal for demanding structural applications.
- Excellent Stress Corrosion Cracking (SCC) Resistance: Compared to other high-strength aluminum alloys like 7075, 7050 exhibits significantly improved resistance to SCC, particularly in thicker sections. This is a critical advantage for components subjected to sustained tensile stresses in corrosive environments.
- Good Fracture Toughness: It maintains good toughness, even at high strength levels, contributing to its damage tolerance in critical structures.
- Good Fatigue Strength: Important for components undergoing cyclic loading.
The specific properties can vary depending on the temper. Common tempers for 7050 plate include T7451 and T7651, which are designed to provide an optimal balance of strength, SCC resistance, and exfoliation corrosion resistance. The T7451 temper, for instance, involves solution heat treatment, stress relief by controlled stretching, and then artificial aging.
Applications
The primary applications for 7050 aluminum plate are found in the aerospace and defense industries. Typical uses include:
- Aircraft fuselage frames and bulkheads
- Wing skins and spars
- Landing gear components
- Other high-stress structural parts requiring a combination of high strength, good fracture toughness, and SCC resistance.
It is often specified for thick plate applications (typically 1.5 inches to 6 inches or more) where the SCC resistance of alloys like 7075-T6 can be a concern. Companies like Shanxi Luokaiwei Steel Company often supply 7050 for these critical applications.
Advantages and Considerations
The main advantage of 7050 over 7075 is its superior SCC resistance and generally better toughness in thicker sections, although 7075 might offer slightly higher peak strength in some tempers. The alloy composition, including higher copper and zirconium content, contributes to these enhanced properties. Reliable material sourcing is crucial; for instance, Shanxi Luokaiwei Steel Company emphasizes quality control for its aluminum products.
Fabrication
- Machinability: 7050 aluminum plate generally exhibits good machinability, comparable to other high-strength aluminum alloys.
- Weldability: Like most 7xxx series alloys, 7050 is not generally recommended for fusion welding due to susceptibility to cracking and significant loss of strength in the heat-affected zone. If welding is unavoidable, specialized techniques and post-weld heat treatments are required, but it’s typically joined mechanically.
- Heat Treatment: The heat treatment processes for 7050 are critical to achieving its desired properties and must be carefully controlled. The T7451 and T7651 tempers involve specific aging cycles.
When selecting 7050 aluminum plate, it’s important to consider the specific temper required for the application, as this dictates the final balance of properties. Reputable suppliers, such as Shanxi Luokaiwei Steel Company, can provide material certifications detailing the alloy composition and mechanical properties.
