7050A Aluminum alloy,Aluminum 7050A alloy，E FORU

### **7050A Aluminum Alloy: Superior Stress Corrosion Resistant Aerospace Grade** **7050A Aluminum Alloy** is a premium, high-strength heat-treatable alloy within the Al-Zn-Mg-Cu (7xxx) series, representing an advanced version of the standard 7050 alloy with tighter compositional controls. It is specifically engineered to provide an exceptional combination of high strength, superior resistance to stress corrosion cracking (SCC), and excellent fracture toughness, particularly in thick sections. This makes it a critical structural material primarily used in the aerospace industry. --- #### **1. Chemical Composition** The enhanced properties of 7050A are achieved through precise control of its chemical composition, particularly with optimized zirconium content and tighter impurity limits. | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 5.7 - 6.7 | Primary strengthening element; forms the main hardening precipitates. | | **Magnesium (Mg)** | 1.8 - 2.7 | Co-operates with Zn to form the strengthening η' (MgZn₂) phase during aging. | | **Copper (Cu)** | 2.0 - 2.6 | Enhances strength and dramatically improves resistance to stress corrosion cracking. | | **Zirconium (Zr)** | 0.08 - 0.15 | Forms fine Al₃Zr dispersoids that inhibit recrystallization, improving toughness and SCC resistance. | | **Iron (Fe)** | ≤ 0.15 | Tighter impurity control to enhance fracture toughness. | | **Silicon (Si)** | ≤ 0.12 | Tighter impurity control to improve ductility and toughness. | | **Manganese (Mn)** | ≤ 0.10 | - | | **Titanium (Ti)** | ≤ 0.06 | - | | **Other Impurities** | ≤ 0.05 each; ≤ 0.15 total | - | | **Aluminum (Al)** | Balance | Base metal. | **Key Difference from 7050:** The "A" variant typically features tighter control over **Iron (Fe)** and **Silicon (Si)** content, and a carefully balanced Zr content, leading to superior consistency in fracture toughness and fatigue performance. --- #### **2. Physical Properties** The physical properties of 7050A alloy are consistent with other high-copper 7xxx series alloys. | Property | Value / Description | | :--- | :--- | | **Density** | ≈ 2.83 g/cm³ (0.102 lb/in³) | | **Melting Range** | ≈ 490°C - 630°C (914°F - 1166°F) | | **Electrical Conductivity** | ≈ 38-42% IACS (International Annealed Copper Standard) | | **Thermal Conductivity** | ≈ 115-135 W/m·K | | **Coefficient of Thermal Expansion** | ≈ 23.5 x 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity (E)** | ≈ 71 GPa (10.3 x 10⁶ psi) | --- #### **3. Mechanical Properties (Typical for T7451 Temper)** The T7451 temper (Solution Heat-Treated, Stress-Relieved by Stretching, and **Over-Aged**) is the most common temper for plate and extruded products, offering the best balance of strength and SCC resistance. | Property | Typical Value | | :--- | :--- | | **Tensile Strength (Ultimate)** | 510 - 540 MPa (74 - 78 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 440 - 470 MPa (64 - 68 ksi) | | **Elongation (in 50 mm / 2 in)** | 10 - 12 % | | **Hardness (Brinell)** | ≈ 140 HB | --- #### **4. Product Applications** 7050A Aluminum Alloy is specified for the most demanding aerospace applications where its through-thickness properties are critical. * **Aerospace Industry (Primary Application):** * **Upper Wing Structures:** Skin and stringers. * **Fuselage Components:** Frames, bulkheads, and longerons. * **Stabilizer Components.** * **Military Aircraft:** Used extensively in fighter aircraft structures. * **Other High-Reliability Applications:** * Critical components in the defense and space industries. --- #### **5. International Standards** 7050A is recognized by major aerospace and international standards bodies. | Standard Body | Alloy Designation | Common Forms | Relevant Standard | | :--- | :--- | :--- | :--- | | **Aluminum Association (AA)** | **7050A** | Plate, Sheet, Extruded Products | AA Teal Sheets / ANSI H35.1 | | **Aerospace (AMS)** | **7050** | Plate, Extrusions, Forgings | AMS 4050 (Plate), AMS 4342 (Plate) | | **European Norm (EN)** | **EN AW-7050A** | Wrought Products | EN 485-2 (Sheet/Plate), EN 755-2 (Extruded Products) | | **ASTM International** | **Aluminum 7050** | - | ASTM B209 (Plate), ASTM B221 (Extrusions) | | **Unified Numbering System (UNS)** | **A97050** | - | SAE J1086 | --- #### **Key Advantages & Summary** * **Excellent Strength-to-Weight Ratio:** Provides high strength while minimizing weight. * **Superior Stress Corrosion Cracking (SCC) Resistance:** The over-aged T74-type temper provides exceptional resistance to failure under tension in corrosive environments. * **Excellent Fracture Toughness:** Particularly in the short-transverse direction (through-thickness), which is critical for thick sections. * **Good Fatigue Performance:** Resistant to crack initiation and propagation under cyclic loading. * **Good Exfoliation Corrosion Resistance.** In conclusion, **7050A Aluminum Alloy** is a specialized, aerospace-grade material optimized for thick-section applications. Its tightly controlled chemistry and availability in over-aged tempers make it the alloy of choice when the design demands a superior balance of **high strength, exceptional fracture toughness, and stress corrosion cracking resistance**, making it a cornerstone material for modern aircraft structures.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2146 gallon liquid totes Special package is available on request.