7449 Aluminum alloy,Aluminum 7449 alloy，E FORU

### **Product Introduction: 7449 Aluminum Alloy** **Aluminum 7449** is a premium, high-strength, heat-treatable alloy belonging to the **Al-Zn-Mg-Cu (7xxx series)** family. It was developed primarily for aerospace applications as a successor to alloys like 7050 and 7150, offering a superior combination of **very high static strength** and **excellent damage tolerance** (fracture toughness). Its composition is optimized to provide exceptional performance, especially in compression-dominated structures. --- ### **1. Chemical Composition** The chemical composition of 7449 is precisely controlled to maximize its strength and toughness. It features high levels of Zinc and Copper, which are key to forming strengthening precipitates. **Typical Composition (% by Weight)** | Element | Content | | :--- | :--- | | **Aluminum (Al)** | Balance | | **Zinc (Zn)** | 7.5 - 8.7 | | **Magnesium (Mg)** | 1.8 - 2.7 | | **Copper (Cu)** | 1.4 - 2.1 | | **Zirconium (Zr)** | 0.10 - 0.18 | | **Iron (Fe)** | ≤ 0.08 | | **Silicon (Si)** | ≤ 0.04 | | **Manganese (Mn)** | ≤ 0.05 | | **Chromium (Cr)** | ≤ 0.05 | | **Titanium (Ti)** | ≤ 0.05 | | **Other Impurities** | ≤ 0.05 each; ≤ 0.15 total | **Key Compositional Notes:** * **High Zn+Mg+Cu:** This combination is the primary driver for its very high strength. * **Low Fe and Si:** Strict limits on these impurities are critical for achieving high fracture toughness and fatigue performance. * **Zirconium (Zr):** Used as a grain refiner to control recrystallization and improve quench sensitivity, leading to more uniform properties in thick sections. --- ### **2. Physical Properties** The physical properties of 7449 are consistent with other high-strength aluminum alloys. | Property | Metric Value | Imperial Value | | :--- | :--- | :--- | | **Density** | ~2.85 g/cm³ | ~0.103 lb/in³ | | **Melting Range** | ~ 475 - 640 °C | ~ 887 - 1184 °F | | **Electrical Conductivity** | ~ 30-35% IACS | - | | **Thermal Conductivity** | ~ 120-130 W/m·K | - | | **Modulus of Elasticity** | 71 GPa | 10.3 x 10⁶ psi | --- ### **3. Mechanical Properties** 7449 is renowned for its high strength, which exceeds that of 7050 and 7150 alloys, while maintaining good damage tolerance. Properties are highly dependent on temper. **Typical Room Temperature Mechanical Properties (T7651 Temper for Plate)** | Property | Value (Metric) | Value (Imperial) | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 620 - 650 MPa | 90 - 94 ksi | | **Tensile Yield Strength (0.2% Offset)** | 580 - 610 MPa | 84 - 88 ksi | | **Elongation at Break** | 10 - 12% | 10 - 12% | **Typical Room Temperature Mechanical Properties (T7951 Temper for Plate)** *This temper offers improved exfoliation corrosion and stress corrosion cracking (SCC) resistance.* | Property | Value (Metric) | Value (Imperial) | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 595 - 625 MPa | 86 - 91 ksi | | **Tensile Yield Strength (0.2% Offset)** | 550 - 580 MPa | 80 - 84 ksi | | **Elongation at Break** | 11 - 13% | 11 - 13% | --- ### **4. International Standards** 7449 is specified in several key international standards, primarily in the aerospace sector. * **Aerospace Material Specifications (AMS):** * **AMS 4412:** Covers Aluminum Alloy 7449 Plate (Solution Heat Treated, Stress Relieved, and Artificially Overaged - T7951 Temper). * **AMS 4413:** Covers Aluminum Alloy 7449 Plate (Solution Heat Treated, Stress Relieved, and Artificially Overaged - T7651 Temper). * **ASTM International:** * **ASTM B209:** Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate. 7449 is included under this standard. * **European Standards (EN):** * It is designated as **EN 4449** under the European aerospace standards. * **OEM Standards:** It is widely used and specified under proprietary standards from major aerospace manufacturers like **Airbus (ABD)** and **Boeing (BMS)**. --- ### **5. Product Applications** 7449 is engineered for the most critical and heavily loaded aerospace structures, primarily in: * **Aerospace Structures:** * **Upper Wing Skins and Cover Plates:** This is the primary application, where its high compressive yield strength is fully utilized to reduce weight and improve fuel efficiency. * **Fuselage Frames and Bulkheads.** * **Wing Spars and Stringers.** * **Defense Applications:** * **Primary structures of military fighter aircraft and transport planes.** * **Components for unmanned aerial vehicles (UAVs).** * **High-Performance Applications:** * Used in some auto-racing components, such as suspension parts, where extreme strength-to-weight ratio is required. --- ### **6. Key Characteristics & Advantages** * **Very High Static Strength:** Offers higher strength than 7050 and 7150, making it ideal for weight-critical structures. * **Excellent Damage Tolerance:** Provides a superior combination of strength and fracture toughness compared to many other high-strength alloys. * **Good Resistance to Exfoliation Corrosion and SCC:** When heat-treated to the T79 or T76 type tempers, it offers sufficient corrosion resistance for aerospace applications. * **Good Property Consistency in Thick Sections:** The alloy's low quench sensitivity ensures good through-thickness properties. ### **Considerations** * **Corrosion Resistance:** Requires protective coatings (anodizing, primers) for long-term service in corrosive environments. The selection of T79 temper over T76 is often for better corrosion performance. * **Weldability:** Generally considered poor for fusion welding; components are typically joined using mechanical fasteners (rivets, bolts). * **Machinability:** Its high strength demands powerful machinery and wear-resistant tooling. * **Cost:** A premium aerospace-grade alloy, it is more expensive than standard alloys due to its advanced composition and stringent processing controls. ### **Conclusion** **Aluminum 7449 alloy** represents a significant advancement in the evolution of high-strength aluminum alloys for aerospace. It is the material of choice for modern aircraft designers seeking to maximize structural efficiency, particularly in upper wing structures, where its unbeatable combination of high compressive strength and damage tolerance leads to lighter, more robust, and more fuel-efficient airframes. It stands as a direct competitor and often superior alternative to other advanced alloys like 7055 and 7150.

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 2211 gallon liquid totes Special package is available on request.