Alclad 7475-T61 Aluminum alloy,Aluminum 7475-T61 alloy，E FORU

### **Product Introduction: Alclad 7475-T61 Aluminum Alloy** **Alclad 7475-T61** is a premium aerospace-grade aluminum product that combines a high-strength, high-toughness **7475 aluminum alloy core** with a thin, metallurgically bonded layer of **high-purity aluminum or a corrosion-prone alloy** on both surfaces. The **T61 temper** specifies that the material is solution heat-treated, stress-relieved by stretching, and then artificially aged to a specific condition that optimizes its combination of strength and resistance to exfoliation corrosion. This product is engineered for applications where superior **fracture toughness** and **fatigue resistance** are critical, and where the Alclad layer provides essential sacrificial corrosion protection. --- ### **1. Chemical Composition** The properties are defined by the core alloy's composition and the Alclad cladding. **A. Core Alloy: 7475 Chemical Composition (% by Weight)** | Element | Content | | :--- | :--- | | **Aluminum (Al)** | Balance | | **Zinc (Zn)** | 5.2 - 6.2 | | **Magnesium (Mg)** | 1.9 - 2.6 | | **Copper (Cu)** | 1.2 - 1.9 | | **Chromium (Cr)** | 0.18 - 0.25 | | **Iron (Fe)** | ≤ 0.12 | | **Silicon (Si)** | ≤ 0.10 | | **Manganese (Mn)** | ≤ 0.06 | | **Titanium (Ti)** | ≤ 0.05 | | **Other Impurities** | ≤ 0.05 each; ≤ 0.15 total | *Key Point: 7475 is a controlled-toughness variant of 7075. It features stricter controls on impurities (Fe, Si) and a specific Zn/Mg/Cu balance to maximize fracture toughness.* **B. Alclad Cladding:** The core is clad on both sides with a layer of **high-purity aluminum (e.g., 7072 alloy)**, typically constituting 1.5% to 5% of the total thickness per side. This layer acts as a **sacrificial anode**, corroding in preference to the strong but less corrosion-resistant 7475 core. --- ### **2. Physical Properties** The physical properties are dominated by the core alloy. | Property | Metric Value | Imperial Value | | :--- | :--- | :--- | | **Density** | ~2.80 g/cm³ | ~0.101 lb/in³ | | **Melting Range** | ~ 475 - 635 °C | ~ 887 - 1175 °F | | **Electrical Conductivity** | ~ 33-40% IACS | - | | **Thermal Conductivity** | ~ 130 W/m·K | - | | **Modulus of Elasticity** | 71 GPa | 10.3 x 10⁶ psi | --- ### **3. Mechanical Properties** The T61 temper provides a specific balance of strength and corrosion resistance. Note that the Alclad layer slightly reduces the overall mechanical properties compared to bare 7475-T76 or T651. **Typical Room Temperature Mechanical Properties (Sheet - T61 Temper)** | Property | Value (Metric) | Value (Imperial) | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 524 - 552 MPa | 76 - 80 ksi | | **Tensile Yield Strength (0.2% Offset)** | 455 - 483 MPa | 66 - 70 ksi | | **Elongation at Break** | 11 - 13% | 11 - 13% | | **Compressive Yield Strength** | ~ 455 MPa | ~ 66 ksi | | **Bearing Yield Strength** | ~ 717 MPa | ~ 104 ksi | | **Fracture Toughness (K꜀)** | Very High | Very High | *The primary advantage of 7475 is its exceptional fracture toughness, which is significantly higher than that of 7075 at comparable strength levels.* --- ### **4. International Standards** Alclad 7475-T61 is covered by key aerospace standards. * **Aerospace Material Specifications (AMS):** * **AMS 4204:** This is the primary specification for "Aluminum Alloy, Sheet and Plate, 7475-T61, Alclad". It defines the requirements for the core composition, cladding, and T61 temper properties. * **ASTM International:** * **ASTM B209:** Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate. 7475 is included under this standard. * **Other Standards:** * It is commonly procured to specific OEM (Original Equipment Manufacturer) standards from companies like **Boeing (BMS)** and **Airbus**, which may have additional requirements. --- ### **5. Product Applications** Alclad 7475-T61 is used in highly critical, damage-tolerant aerospace structures. * **Aerospace Structures:** * **Aircraft Fuselage Skins:** Its high fracture toughness and excellent fatigue crack propagation resistance make it ideal for containing cracks and ensuring structural integrity. * **Wing Skins:** Especially for lower wings and other areas subject to tensile loads. * **Bulkheads and Frame Members.** * **Military Aircraft Canopies and Transparencies (as a high-strength frame).** * **Space Applications:** * **Fuel Tanks and Structural Components for Launch Vehicles and Satellites.** * **Other High-Performance Applications:** * **High-performance bicycle frames** and components in competitive racing. --- ### **6. Key Characteristics & Advantages** * **Exceptional Fracture Toughness:** This is the defining characteristic of 7475. It is highly resistant to crack propagation. * **Excellent Fatigue Performance:** The Alclad surface and the tough core work together to resist the initiation and growth of fatigue cracks. * **Superior Corrosion Protection:** The Alclad layer provides sacrificial (cathodic) protection to the core, drastically improving resistance to exfoliation and pitting corrosion compared to bare 7xxx series alloys. * **Good Strength-to-Weight Ratio:** While not the absolute strongest 7xxx alloy, it offers a superb balance of strength, toughness, and low density. ### **Considerations** * **Strength vs. Other Alloys:** Its strength is lower than that of peak-aged 7075-T6 or 7150-T6. It is selected for toughness, not maximum strength. * **Cladding Thickness:** The Alclad layer is integral to its performance but must be accounted for in machining and design, as it is softer than the core. * **Weldability:** Like most high-strength 7xxx alloys, it is generally not recommended for fusion welding; mechanical fastening is the preferred joining method. * **Cost:** A premium, specialty aerospace alloy, it is more expensive than standard grades like 2024 or 7075. ### **Conclusion** **Alclad 7475-T61 Aluminum Alloy** is a specialized, high-reliability material designed for the most demanding damage-tolerant aerospace applications. Its unparalleled fracture toughness, combined with the built-in corrosion protection of the Alclad coating, makes it the material of choice for critical airframe components like fuselage and wing skins, where safety and long-term durability under cyclic loading are paramount. It represents the optimal choice when damage tolerance is a more critical design driver than pure static strength.

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 2212 gallon liquid totes Special package is available on request.