Alclad 7178-T6, T651 Aluminum alloy,Aluminum 7178-T6, T651 alloy，E FORU

### **Alclad 7178-T6, T651 Aluminum Alloy: Ultra-High Strength Clad Aerospace Alloy** **Alclad 7178-T6/T651 Aluminum Alloy** represents one of the highest strength commercially available aluminum alloys, featuring a protective cladding layer that provides superior corrosion resistance while maintaining the exceptional mechanical properties of the 7178 core alloy. This combination makes it ideal for the most demanding aerospace and defense applications. --- #### **1. Chemical Composition** **Core Alloy (7178):** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 6.3 - 7.3 | Primary strengthening element | | **Magnesium (Mg)** | 2.4 - 3.1 | Enhances strength and stress corrosion resistance | | **Copper (Cu)** | 1.6 - 2.4 | Improves strength and precipitation hardening | | **Chromium (Cr)** | 0.18 - 0.28 | Controls grain structure and improves toughness | | **Iron (Fe)** | ≤ 0.50 | Impurity element | | **Silicon (Si)** | ≤ 0.40 | Impurity element | | **Manganese (Mn)** | ≤ 0.30 | - | | **Titanium (Ti)** | ≤ 0.20 | - | | **Aluminum (Al)** | Balance | Base metal | **Cladding Layer:** - Typically 7072 aluminum alloy (Al-Zn) or high-purity aluminum - Thickness: 1.5-4% of total thickness per side - Provides electrochemical corrosion protection --- #### **2. Understanding Tempers and Alclad Construction** **T6 Temper:** - Solution heat-treated and artificially aged to peak strength - Maximum strength condition - May contain residual stresses from quenching **T651 Temper:** - Solution heat-treated, stress-relieved by stretching, and artificially aged - Reduced residual stresses - Improved dimensional stability for machining - Preferred for critical applications **Alclad Feature:** - Sacrificial corrosion protection - Metallurgically bonded cladding - Maintains core mechanical properties - Enhanced environmental durability --- #### **3. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.82 g/cm³ (0.102 lb/in³) | | **Melting Range** | 477°C - 638°C (890°F - 1180°F) | | **Electrical Conductivity** | 32-36% IACS | | **Thermal Conductivity** | 120-140 W/m·K | | **Coefficient of Thermal Expansion** | 23.5 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 71 GPa (10.3 × 10⁶ psi) | --- #### **4. Mechanical Properties (Typical)** | Property | T6 Temper | T651 Temper | | :--- | :--- | :--- | | **Tensile Ultimate Strength** | 510 - 560 MPa (74 - 81 ksi) | 500 - 550 MPa (73 - 80 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 450 - 500 MPa (65 - 73 ksi) | 440 - 490 MPa (64 - 71 ksi) | | **Elongation** | 6-10% | 7-11% | | **Compression Yield Strength** | 460 - 510 MPa (67 - 74 ksi) | 450 - 500 MPa (65 - 73 ksi) | | **Shear Strength** | 300 - 340 MPa (44 - 49 ksi) | 290 - 330 MPa (42 - 48 ksi) | | **Fatigue Strength** | 160 - 190 MPa (23 - 28 ksi) | 155 - 185 MPa (22 - 27 ksi) | | **Brinell Hardness** | 140 - 155 HB | 135 - 150 HB | *Note: Slightly lower than bare 7178 due to cladding layer* --- #### **5. Product Applications** **Alclad 7178-T6/T651** is used in the most demanding applications: * **Aerospace Structures:** * Aircraft wing and fuselage skins * Primary structural frames * Spar caps and stringers * Military aircraft components * **Defense Applications:** * Military vehicle armor * Missile and rocket components * Defense system structures * **High-Performance Applications:** * Racing vehicle components * High-stress structural members * Critical machinery parts * **Space Applications:** * Space launch vehicle structures * Satellite components --- #### **6. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7178-T6/T651 Alclad | AA Teal Sheets | | **ASTM International** | 7178-T6/T651 Alclad | ASTM B209 | | **Aerospace (AMS)** | AMS 4048 | Alclad 7178 Sheet | | **Military Standards** | MIL-A-12545 | Aluminum Alloy Armor | | **European Norm** | EN AW-7178 Alclad | EN 485-2 | --- #### **7. Key Characteristics** **Advantages:** - **Exceptional strength-to-weight ratio** - **Superior corrosion resistance** with sacrificial cladding - **Excellent fatigue performance** - **High damage tolerance** - **Proven reliability** in aerospace applications - **Good machinability** in aged condition **Limitations:** - **Higher cost** than non-clad alternatives - **Reduced strength** compared to bare 7178 (due to cladding) - **Limited formability** in aged condition - **Requires specialized welding** techniques --- #### **8. Manufacturing Considerations** * **Machining:** Excellent machinability with proper tooling * **Forming:** Limited formability in T6/T651 temper * **Welding:** Requires specialized techniques * **Heat Treatment:** Solution treated at 460-475°C, aged at 115-130°C * **Surface Treatment:** Excellent for painting and coating --- #### **9. Special Features** **Alclad 7178-T6/T651** offers unique advantages: * **Corrosion Protection:** Cladding sacrificially protects core in corrosive environments * **Strength Level:** Among the strongest commercially available aluminum alloys * **Quality Assurance:** Strict control of cladding thickness and bond integrity * **Performance Heritage:** Extensive use in critical aerospace applications **Comparison with 7075 Alclad:** - Approximately 10-15% higher strength - Similar corrosion resistance - Higher cost but superior mechanical properties - Preferred for most critically stressed components --- #### **10. Performance Characteristics** - **Fatigue Resistance:** Excellent for highly stressed aircraft structures - **Stress Corrosion Cracking:** Improved resistance due to cladding - **Fracture Toughness:** Good for ultra-high strength alloy - **Temperature Stability:** Maintains properties up to 120°C **Alclad 7178-T6/T651 Aluminum Alloy** represents the pinnacle of aluminum alloy technology for applications requiring the ultimate combination of strength and corrosion resistance. Its extensive use in aerospace and defense applications demonstrates its capability to perform in the most demanding environments while providing long-term durability through its sacrificial cladding protection system. The T651 temper provides additional benefits for precision components where dimensional stability and reduced residual stresses are essential for performance and manufacturability.

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 2196 gallon liquid totes Special package is available on request.