7255 Aluminum alloy,Aluminum 7255 alloy，E FORU

### **7255 Aluminum Alloy: Ultra-High Strength Aerospace Alloy** **7255 Aluminum Alloy** is an ultra-high strength aluminum-zinc-magnesium-copper alloy developed for the most demanding aerospace applications requiring the highest possible strength-to-weight ratio combined with good damage tolerance and corrosion resistance. This alloy represents the pinnacle of aluminum alloy technology for critical aircraft structures. --- #### **1. Chemical Composition** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 7.6 - 8.4 | Primary strengthening element through formation of MgZn₂ precipitates | | **Magnesium (Mg)** | 1.8 - 2.3 | Enhances strength and age-hardening response | | **Copper (Cu)** | 1.9 - 2.5 | Improves strength and stress corrosion cracking resistance | | **Zirconium (Zr)** | 0.08 - 0.15 | Controls grain structure and inhibits recrystallization | | **Iron (Fe)** | ≤ 0.10 | Tightly controlled impurity for improved toughness | | **Silicon (Si)** | ≤ 0.08 | Tightly controlled impurity for improved ductility | | **Manganese (Mn)** | ≤ 0.06 | - | | **Chromium (Cr)** | ≤ 0.04 | - | | **Titanium (Ti)** | ≤ 0.06 | - | | **Other Elements** | ≤ 0.05 each; ≤ 0.15 total | - | | **Aluminum (Al)** | Balance | Base metal | --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.83 g/cm³ (0.102 lb/in³) | | **Melting Range** | 475°C - 638°C (887°F - 1180°F) | | **Electrical Conductivity** | 34-38% IACS | | **Thermal Conductivity** | 120-135 W/m·K | | **Coefficient of Thermal Expansion** | 23.4 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 71.5 GPa (10.4 × 10⁶ psi) | --- #### **3. Mechanical Properties (Typical for T7951 Temper)** | Property | Typical Value | | :--- | :--- | | **Tensile Ultimate Strength** | 620 - 670 MPa (90 - 97 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 590 - 640 MPa (86 - 93 ksi) | | **Elongation** | 7-10% | | **Compression Yield Strength** | 580 - 630 MPa (84 - 91 ksi) | | **Shear Strength** | 350 - 390 MPa (51 - 57 ksi) | | **Fatigue Strength** | 190 - 220 MPa (28 - 32 ksi) | | **Fracture Toughness** | Good | --- #### **4. Product Applications** **7255 Aluminum Alloy** is used in the most critically stressed aerospace applications: * **Aircraft Structures:** * Upper wing skins and planks * Wing spar caps * Fuselage frames * Stabilizer components * Primary structural members * **Military Applications:** * Fighter aircraft primary structures * Military transport aircraft components * Missile structures * **Space Applications:** * Launch vehicle fuel tanks * Spacecraft primary structures * Rocket components * **Commercial Aviation:** * Next-generation commercial aircraft wings * Fuselage stringers * Primary load-bearing structures --- #### **5. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7255 | AA Teal Sheets | | **ASTM International** | 7255 | ASTM B209 | | **Aerospace (AMS)** | 7255 | AMS 4343 | | **European Norm** | EN AW-7255 | EN 485-2 | | **Unified Numbering System** | A97255 | UNS Registry | --- #### **6. Key Characteristics** **Advantages:** * **Ultra-high strength-to-weight ratio** * **Excellent fatigue performance** * **Good damage tolerance** * **Superior corrosion resistance** for strength level * **Good fracture toughness** * **Enhanced thermal stability** * **Excellent cryogenic properties** **Limitations:** * **Highest cost** among commercial aluminum alloys * **Requires extremely precise** heat treatment control * **Limited formability** in aged condition * **Specialized manufacturing** processes required * **Challenging machining** operations --- #### **7. Manufacturing Considerations** * **Machining:** Requires advanced tooling and techniques * **Forming:** Must be formed in annealed condition * **Welding:** Requires specialized welding methods * **Heat Treatment:** Critical control of solution treatment and aging * **Surface Treatment:** Excellent for anodizing and coating --- #### **8. Special Features** **7255 Aluminum Alloy** offers exceptional performance characteristics: * **Strength Level:** Highest strength commercially available aluminum alloy * **Cryogenic Performance:** Excellent properties at low temperatures * **Property Optimization:** Best-in-class strength-toughness combination * **Quality Requirements:** Stringent quality control standards **Comparison with 7055 Alloy:** - Approximately 5-7% higher strength - Improved damage tolerance - Better corrosion resistance - Superior thermal stability --- #### **9. Performance in Service** * **Fatigue Performance:** Exceptional for highly stressed structures * **Corrosion Resistance:** Good with proper protection * **Damage Tolerance:** Adequate for critical applications * **Temperature Capability:** Excellent from cryogenic to elevated temperatures **7255 Aluminum Alloy** represents the ultimate achievement in aluminum alloy development for aerospace applications. The alloy's exceptional strength properties make it the material of choice for the most critically stressed aircraft components where every kilogram of weight savings translates directly into improved performance and efficiency. While demanding special attention in manufacturing and requiring premium costs, 7255 provides unparalleled performance that justifies its use in next-generation aircraft designs where pushing the boundaries of performance and efficiency are paramount requirements.

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 2206 gallon liquid totes Special package is available on request.