Alclad 7178-O Aluminum alloy,Aluminum 7178-O alloy，E FORU

### **Alclad 7178-O Aluminum Alloy: Annealed High-Strength Clad Alloy** **Alclad 7178-O Aluminum Alloy** consists of a high-strength 7178 aluminum alloy core metallurgically bonded with a thin layer of pure aluminum or aluminum alloy cladding. The O temper (annealed) condition represents the softest state, providing maximum formability while maintaining the high-strength potential of the 7178 core alloy after subsequent heat treatment. --- #### **1. Chemical Composition** **Core Alloy (7178):** | Element | Content (%) (Typical) | Role in the Alloy | | :--- | :--- | :--- | | **Zinc (Zn)** | 6.3 - 7.3 | Primary strengthening element through formation of MgZn₂ precipitates | | **Magnesium (Mg)** | 2.4 - 3.1 | Enhances strength and age-hardening response | | **Copper (Cu)** | 1.6 - 2.4 | Improves strength and stress corrosion cracking resistance | | **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 | - | | **Other Elements** | ≤ 0.05 each | - | | **Aluminum (Al)** | Balance | Base metal | **Cladding Layer:** - Typically 7072 aluminum alloy (Al-Zn) or high-purity aluminum - Thickness: 2-5% of total thickness per side - Provides sacrificial corrosion protection --- #### **2. 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** | 115-135 W/m·K | | **Coefficient of Thermal Expansion** | 23.5 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 71 GPa (10.3 × 10⁶ psi) | --- #### **3. Mechanical Properties (Typical - O Temper)** | Property | Typical Value | | :--- | :--- | | **Tensile Ultimate Strength** | 230 - 270 MPa (33 - 39 ksi) | | **Tensile Yield Strength (0.2% Offset)** | 110 - 150 MPa (16 - 22 ksi) | | **Elongation** | 10-14% | | **Shear Strength** | 160 - 190 MPa (23 - 28 ksi) | | **Brinell Hardness** | 65 - 80 HB | *Note: Properties after solution heat treatment and aging (T6 temper):* - *Tensile Strength: 530-590 MPa (77-86 ksi)* - *Yield Strength: 470-530 MPa (68-77 ksi)* --- #### **4. Product Applications** **Alclad 7178-O** is used in applications requiring both formability and high strength potential: * **Aerospace Components:** * Aircraft structural components requiring forming * Wing skins and panels * Fuselage components * Military aircraft parts * **High-Performance Applications:** * Racing components * High-stress structural parts * Critical machinery components * **Marine and Defense:** * Marine aircraft components * Defense system structures * Armored vehicle components --- #### **5. International Standards** | Standard Body | Designation | Specification | | :--- | :--- | :--- | | **Aluminum Association** | 7178-O Alclad | AA Teal Sheets | | **ASTM International** | 7178-O Alclad | ASTM B209 | | **Aerospace (AMS)** | AMS 4047 | Clad 7178 Sheet | | **European Norm** | EN AW-7178 Alclad | EN 485-2 | | **Unified Numbering System** | A97178 | UNS Registry | --- #### **6. Key Characteristics** **Advantages:** - **Excellent corrosion resistance** due to sacrificial cladding - **High strength potential** after heat treatment - **Maximum formability** in O temper - Good fatigue resistance - Superior environmental durability - Excellent strength-to-weight ratio after aging **Limitations:** - Lower strength in O temper requires subsequent heat treatment - Higher cost than non-clad alternatives - Cladding reduces overall strength slightly - Requires specialized processing equipment --- #### **7. Manufacturing Considerations** * **Forming:** Excellent in O temper for complex shapes * **Heat Treatment:** Can be solution treated and aged after forming * **Machining:** Good machinability after heat treatment * **Joining:** Good weldability with proper techniques * **Surface Treatment:** Excellent for painting and coating --- #### **8. Special Features** **Alclad 7178-O** offers unique advantages: * **Corrosion Protection:** Cladding sacrificially protects core from corrosion * **Forming Flexibility:** Can be formed in O temper and strengthened later * **High Strength Potential:** Achieves 7178-T6 properties after heat treatment * **Damage Tolerance:** Cladding provides additional surface protection * **Maintenance Reduction:** Extended service life in corrosive environments **Typical Manufacturing Sequence:** 1. Form component in O temper condition 2. Solution heat treat at 460-475°C 3. Quench rapidly 4. Artificial age at 115-130°C 5. Final machining and finishing --- #### **9. Quality Assurance** - Cladding thickness controlled to specifications - Metallurgical bond integrity ensured - Chemical composition verified - Mechanical properties tested - Surface quality inspected **Alclad 7178-O Aluminum Alloy** provides an optimal solution for applications requiring both severe formability during manufacturing and high strength with excellent corrosion resistance in service. The combination of 7178's strength potential with sacrificial cladding protection makes it particularly valuable for aerospace and defense applications where performance and durability are critical.

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 2195 gallon liquid totes Special package is available on request.