Alclad 2024-T861 Aluminum alloy,Aluminum 2024-T861 alloy,E FORU

### **Alclad 2024-T861 Aluminum Alloy Product Introduction** **Overview** Alclad 2024-T861 is a high-performance aluminum-copper alloy that undergoes an advanced thermal-mechanical treatment process to achieve superior mechanical properties. The T861 temper designation indicates the material has been solution heat-treated, cold worked with greater mechanical stretching (typically 6-8%), and artificially aged to develop maximum strength characteristics while maintaining adequate toughness. This specialized temper, combined with Alclad corrosion protection, provides an optimal solution for critical aerospace structures demanding the highest strength-to-weight ratio in the 2024 alloy system. --- #### **1. Chemical Composition** **Core Material: 2024 Alloy** | Element | Content (%) | |---------|-------------| | **Aluminum (Al)** | Balance | | **Copper (Cu)** | 3.8 - 4.9 | | **Magnesium (Mg)** | 1.2 - 1.8 | | **Manganese (Mn)** | 0.30 - 0.9 | | **Iron (Fe)** | ≤ 0.20 | | **Silicon (Si)** | ≤ 0.15 | | **Zinc (Zn)** | ≤ 0.10 | | **Other Elements** | ≤ 0.15 total | **Cladding Material** - **Alloy:** 1230, 1050, or 1060 series aluminum - **Purity:** ≥99.0% aluminum content - **Coating Thickness:** Typically 1.5-5% per side of total thickness - **Protection Method:** Sacrificial cathodic protection --- #### **2. Physical Properties** | Property | Value / Description | |----------|---------------------| | **Density** | 2.78 g/cm³ (0.100 lb/in³) | | **Melting Range** | 500°C - 638°C (932°F - 1180°F) | | **Electrical Conductivity** | 28-33% IACS | | **Thermal Conductivity** | 115-125 W/m·K (at 25°C) | | **Coefficient of Thermal Expansion** | 23.2 × 10⁻⁶/°C (20-100°C) | | **Modulus of Elasticity** | 73.1 GPa (10,600 ksi) | | **Poisson's Ratio** | 0.33 | --- #### **3. Mechanical Properties** **Typical Mechanical Properties:** | Property | Value | |----------|-------| | **Tensile Strength** | 470-510 MPa (68-74 ksi) | | **Yield Strength (0.2% Offset)** | 390-430 MPa (57-62 ksi) | | **Elongation in 2 inches** | 5-8% | | **Shear Strength** | 285-310 MPa (41-45 ksi) | | **Fatigue Strength** | 145 MPa (21 ksi) | | **Brinell Hardness** | 135-145 HB | | **Fracture Toughness (K_IC)** | 22-26 MPa·√m | | **Compressive Yield Strength** | 380-420 MPa (55-61 ksi) | *Note: The increased cold working (6-8% stretch) in T861 provides higher strength but reduced ductility compared to T81/T851 tempers.* --- #### **4. International Standards** | Standard System | Designation | Product Form | |-----------------|-------------|--------------| | **ASTM** | ASTM B209 | Sheet & Plate | | **AMS** | AMS 4037 | Sheet | | **AMS** | AMS 4080 | Plate | | **MIL** | MIL-DTL-6075 | Sheet | | **EN** | EN AW-2024A [T861] | Sheet/Plate | | **ISO** | ISO 6361 | Wrought Products | --- #### **5. Product Applications** **Critical Aerospace Structures:** - Aircraft lower wing skins and covers - Primary fuselage structural components - Wing spar chords and caps - Aircraft landing gear support structures - Helicopter rotor components **Defense and Space Applications:** - Military aircraft primary structures - Missile airframes and launch structures - Satellite structural components - Armored vehicle structural elements - Rocket interstage structures **Special Applications:** - High-performance racing components - Critical machined structural parts - Applications requiring maximum strength-to-weight ratio - Components subject to high compressive loads --- #### **6. Key Advantages & Considerations** **Advantages:** - ✅ **Maximum Strength Capability:** Highest strength properties in 2024 alloy series - ✅ **Superior Strength-to-Weight Ratio:** Optimal for weight-critical applications - ✅ **Enhanced Fatigue Performance:** Excellent resistance to cyclic loading - ✅ **Improved Stress-Corrosion Resistance:** Better than T6 temper despite higher strength - ✅ **Excellent Dimensional Stability:** High degree of cold working minimizes residual stresses - ✅ **Corrosion Protection:** Alclad coating provides environmental durability **Considerations:** - ⚠️ **Reduced Ductility:** Lower elongation requires careful manufacturing planning - ⚠️ **Limited Formability:** Essentially no capability for post-heat treatment forming - ⚠️ **Machining Challenges:** Requires specialized tools and techniques - ⚠️ **Cost Premium:** Multiple processing steps increase material cost - ⚠️ **Directional Properties:** Mechanical properties vary with grain direction - ⚠️ **Welding Not Recommended:** Unsuitable for fusion welding applications --- **Processing Characteristics** **T861 Thermal-Mechanical Treatment:** 1. Solution heat treatment at 490-500°C (915-932°F) 2. Rapid quenching to room temperature 3. Substantial cold working (6-8% permanent stretch) 4. Artificial aging at controlled temperature and time parameters 5. Final inspection and quality verification **Performance Characteristics:** - Maximum strength development through enhanced cold working - Improved grain structure alignment - Reduced susceptibility to stress-corrosion cracking - Superior fatigue crack initiation resistance - Stable mechanical properties under service conditions **Conclusion** Alclad 2024-T861 Aluminum Alloy represents the ultimate strength development in the 2024 alloy system, providing the highest mechanical properties achievable while maintaining the corrosion protection benefits of Alclad coating. The extensive cold working process (6-8% stretch) differentiates T861 from other tempers, delivering exceptional strength characteristics essential for the most demanding aerospace applications. While the material demands sophisticated manufacturing approaches and carries a cost premium, its unparalleled performance in primary aircraft structures justifies its use where every kilogram of weight savings and every megapascal of strength contribute to overall system performance. The combination of maximum strength, good fatigue resistance, and environmental protection makes Alclad 2024-T861 the material of choice for engineers designing critical components where structural efficiency and reliability are paramount.

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 1540 gallon liquid totes Special package is available on request.