2618-T61 Aluminum alloy,Aluminum 2618-T61 alloy,E FORU

### **Aluminum Alloy 2618-T61 Product Introduction** **Aluminum Alloy 2618-T61** is a heat-treated variant of the classic high-temperature aluminum alloy 2618. The **T61 temper** specifically denotes a process of Solution Heat Treatment followed by Controlled Cooling (typically in air or a less severe quench than for T6) and then Artificial Aging. This temper is designed to achieve a favorable balance of strength, dimensional stability, and reduced internal stresses, making it particularly suitable for complex forgings and components where minimizing distortion is critical. --- #### **1. Chemical Composition** The composition is identical to that of the base 2618 alloy, carefully balanced for high-temperature performance. Key elements are (typical values in weight %): | Element | Content (%) | | :--- | :--- | | **Copper (Cu)** | 1.8 - 2.7 | | **Magnesium (Mg)** | 1.2 - 1.8 | | **Iron (Fe)** | 0.9 - 1.4 | | **Nickel (Ni)** | 0.8 - 1.4 | | **Silicon (Si)** | 0.15 - 0.25 | | **Titanium (Ti)** | 0.04 - 0.10 | | **Zinc (Zn)** | 0.10 max | | **Manganese (Mn)** | 0.15 max | | **Other Impurities** | each 0.05 max, total 0.15 max | | **Aluminum (Al)** | Balance | * **Copper (Cu) & Magnesium (Mg):** Primary strengthening elements forming S' (Al₂CuMg) precipitates during aging. * **Iron (Fe) & Nickel (Ni):** Form the stable **Al₉FeNi** phase, essential for high-temperature strength and creep resistance. * **Silicon (Si):** Aids in the precipitation hardening process. --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | Approximately 2.76 g/cm³ | | **Melting Range** | ~ 550 - 650 °C | | **Modulus of Elasticity** | Approximately 74 GPa (10.7 x 10⁶ psi) | | **Thermal Conductivity** | ~ 120-140 W/m·K (at 25°C) | | **Electrical Conductivity** | ~ 35-42% IACS | | **Coefficient of Thermal Expansion** | ~ 22.0 x 10⁻⁶ /K | --- #### **3. Mechanical Properties (T61 Temper)** The T61 temper offers a excellent balance of properties, with strength typically very close to, but slightly lower than, the T6 temper, in exchange for better dimensional stability. * **Tensile Ultimate Strength:** 430 - 470 MPa (62 - 68 ksi) * **Tensile Yield Strength (0.2% Offset):** 360 - 400 MPa (52 - 58 ksi) * **Elongation (% in 50mm):** 8 - 12% * **Elevated Temperature Performance:** Retains excellent strength and creep resistance at temperatures up to 200°C (392°F), similar to the T6 condition. * **Dimensional Stability:** The controlled cooling rate of the T61 process results in lower residual stresses, reducing the risk of distortion during subsequent machining. --- #### **4. International Standards** The 2618 alloy in T6-type tempers is covered by major aerospace and material standards. The specific "T61" callout is often found within detailed procurement specifications. * **AMS (Aerospace Material Specification):** * **AMS 4124** (Sheet and Plate - typically supplied in T6 or T61) * **AMS 4125** (Forging Stock - commonly specified in T61 for forged components) * **EN (European Norm):** **EN 2118** (A key standard for 2618 alloy forgings in the aerospace industry). * **ISO:** **ISO 6361-2** (Wrought Aluminum and Aluminum Alloy Sheets, Strips and Plates). * **Customer Specifications:** Often directly specified by OEMs in aerospace for critical forged parts. --- #### **5. Product Applications** The 2618-T61 condition is primarily selected for complex, high-integrity components that require extensive machining after heat treatment. * **Aerospace:** * **Aircraft Engine Pistons and Cylinder Heads** * **Compressor Wheels and Turbine Blades/Impellers** * **Wheels and Brake Components** * **Large, Complex Structural Forgings** (e.g., bulkheads, pylons) * **Automotive (High-Performance):** * **Forged Racing Pistons** - The T61 temper's stability is crucial for maintaining precise tolerances. * **General Engineering:** * **Plastic Injection Molds** requiring high dimensional stability under thermal cycling. --- #### **6. Key Advantages of the T61 Temper** * **Reduced Residual Stress:** The primary advantage over T6. The controlled cooling minimizes internal stresses, which is critical for complex parts to prevent warping during final machining. * **Excellent Machinability:** The combination of high strength and low internal stress allows for predictable and stable machining to precise tolerances. * **Superior High-Temperature Performance:** Maintains the core benefit of the 2618 alloy, with excellent strength retention and creep resistance up to ~200°C. * **Good Strength-Ductility Balance:** Provides high strength while maintaining adequate toughness for demanding applications. * **Ideal for Complex Forgings:** The T61 process is often the preferred heat treatment for large or intricate forged components where distortion control is paramount. **Conclusion** **Aluminum Alloy 2618-T61** is a specialized temper of a high-performance alloy, engineered for applications where dimensional stability is as critical as high-temperature strength. By opting for the T61 temper over the T6, manufacturers gain a material that is more predictable and stable during machining, making it the preferred choice for complex, safety-critical components in aerospace and high-performance motorsports. It represents a careful optimization for manufacturability without sacrificing the core high-temperature capabilities of the 2618 system.

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 1642 gallon liquid totes Special package is available on request.