2724 Aluminum alloy,Aluminum 2724 alloy,E FORU

### **Aluminum Alloy 2724 Product Introduction** **Aluminum Alloy 2724** is a state-of-the-art, ultra-high-strength, and damage-tolerant Al-Cu-Mg alloy developed for the most demanding primary structural applications in next-generation aircraft. It represents a significant step forward in the evolution of 2XXX series alloys, offering a remarkable combination of **higher static strength** and **exceptional fatigue crack growth resistance** compared to its predecessors like 2524 and 2624. Engineered to push the boundaries of weight reduction and structural efficiency, AA2724 is targeted at lower wing and fuselage applications where maximum performance is required. --- #### **1. Chemical Composition** The composition of AA2724 is a highly optimized refinement, building upon the principles of 2524/2624 but with adjustments aimed at further enhancing strength. Key elements are (typical values in weight % based on industry data): | Element | Content (%) | | :--- | :--- | | **Copper (Cu)** | 4.2 - 4.8 | *(Higher than 2524/2624)* | | **Magnesium (Mg)** | 1.2 - 1.8 | | **Manganese (Mn)** | 0.45 - 0.7 | | **Zinc (Zn)** | 0.25 - 0.35 | *(A key differentiating element)* | | **Iron (Fe)** | 0.08 max | *(Very tight control)* | | **Silicon (Si)** | 0.06 max | *(Very tight control)* | | **Titanium (Ti)** | 0.10 max | | **Other Impurities** | each 0.05 max, total 0.15 max | | **Aluminum (Al)** | Balance | * **Higher Copper (Cu) and added Zinc (Zn):** This combination is a key driver for the alloy's higher strength. The presence of Zn, along with Cu and Mg, contributes to the formation of a higher density of strengthening precipitates (building on the S' phase) during aging. * **Critically Low Iron (Fe) and Silicon (Si):** Maintains the essential cleanliness required for supreme fracture toughness and fatigue performance by minimizing brittle constituent particles. --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | Approximately 2.79 g/cm³ | | **Melting Range** | ~ 500 - 650 °C | | **Modulus of Elasticity** | Approximately 73 GPa (10.6 x 10⁶ psi) | | **Thermal Conductivity** | ~ 120-130 W/m·K (at 25°C) | | **Electrical Conductivity** | ~ 30-40% IACS | | **Coefficient of Thermal Expansion** | ~ 23.2 x 10⁻⁶ /K | --- #### **3. Mechanical Properties** AA2724 is supplied in T3-type tempers (e.g., T39). Its defining characteristic is its superior strength-toughness combination compared to other damage-tolerant alloys. * **Tensile Ultimate Strength:** 495 - 530 MPa (72 - 77 ksi) * **Tensile Yield Strength:** 415 - 450 MPa (60 - 65 ksi) * **Elongation:** 10 - 14% * **Fracture Toughness:** Very high, maintaining excellent damage tolerance despite the significant increase in strength. * **Fatigue Crack Growth Resistance:** Outstanding, providing superior resistance to the propagation of fatigue cracks. **Comparison Note:** The yield strength of 2724-T39 is significantly higher than that of 2524-T3 and 2624-T39, while maintaining comparable toughness and fatigue performance. --- #### **4. International Standards** As a very advanced and proprietary alloy, its specifications are often closely held by the developing company and the aerospace OEMs that use it. * **OEM Specifications:** This alloy is strongly associated with **The Boeing Company** and is a key material for the **Boeing 777X** program. Its procurement is governed by detailed Boeing proprietary material specifications. * **AMS:** A specific AMS number may be under development or restricted. It is often produced to meet the requirements of a overarching specification like **AMS 4413** (for 2397 plate) but to the proprietary chemistry and properties of 2724. * **Metallurgical Concept:** It is part of a family of alloys developed through the US Air Force's "Advanced Aluminum Alloys" program, aiming to replace 2024 and 2124 with higher-performance variants. --- #### **5. Product Applications** AA2724 is designed for the most critically stressed structures in modern aircraft, where its higher strength allows for significant weight savings. * **Aircraft Structures:** * **Lower Wing Skins and Panels:** This is the primary application. The higher tensile yield strength is directly utilized to withstand wing bending loads, enabling thinner gauges and substantial weight reduction. * **Upper Wing Skins** (for compression loads). * **Fuselage Frames and Keel Beams.** * **Primary Application:** It is extensively used in the **Boeing 777X** wings, which are the longest composite wings on a commercial aircraft, and the use of 2724 in the surrounding structure and attachments is critical for performance. --- #### **6. Key Advantages** * **Ultra-High Strength for Damage-Tolerant Alloys:** Offers the highest strength among the modern damage-tolerant alloys (2524, 2624, 2724 family), providing a clear step-change in performance. * **Excellent Damage Tolerance:** Maintains very good fracture toughness and fatigue crack growth resistance, a remarkable achievement given its high strength. * **Maximum Weight Reduction:** The high strength-to-weight ratio is the primary benefit, enabling lighter airframe structures and contributing directly to improved fuel efficiency and payload capacity. * **Next-Generation Enabler:** Its development was crucial for meeting the aggressive performance targets of next-generation aircraft like the Boeing 777X. **Conclusion** **Aluminum Alloy 2724** represents the current pinnacle of high-strength, damage-tolerant aluminum alloy development for aerospace. By strategically adjusting the chemistry, particularly with higher copper and the addition of zinc, it delivers a significant boost in static strength without sacrificing the critical damage tolerance required for primary aircraft structures. Its deployment on flagship programs like the Boeing 777X underscores its role as a key enabling technology for the future of efficient and high-performance aviation, pushing the limits of what is possible with aluminum airframe materials.

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 1644 gallon liquid totes Special package is available on request.