2018-T61 Aluminum alloy,Aluminum 2018-T61 alloy,E FORU

### **2018-T61 Aluminum Alloy Product Introduction** **Overview** 2018-T61 Aluminum Alloy is a high-strength, heat-treatable aluminum-copper alloy, strengthened through artificial aging (precipitation hardening). The "T61" temper indicates that the material has been solution heat-treated, quenched, and then artificially aged to a specific condition that provides a high level of strength and improved dimensional stability. This alloy is characterized by its excellent machinability and good elevated temperature strength, making it a premium choice for forged components, particularly in the aerospace and automotive industries. --- #### **1. Chemical Composition (Typical Weight %)** The chemical composition of 2018 Aluminum Alloy is distinct from 2017, with additions of silicon and iron that contribute to its forging characteristics and high-temperature performance. | Element | Minimum (%) | Maximum (%) | Notes | | :--- | :--- | :--- | :--- | | **Aluminum (Al)** | Balance | Balance | - | | **Copper (Cu)** | 3.5 | 4.5 | Primary strengthening element. | | **Magnesium (Mg)** | 0.45 | 0.9 | Contributes to strength via heat treatment. | | **Silicon (Si)** | 0.10 | 0.25 | Improves casting and forging fluidity. | | **Iron (Fe)** | 0.9 | 1.4 | Enhances strength and high-temperature properties. | | **Nickel (Ni)** | 1.7 | 2.3 | **Key element** that improves strength and stability at elevated temperatures. | | **Manganese (Mn)** | - | 0.20 | Impurity. | | **Zinc (Zn)** | - | 0.10 | Impurity. | | **Titanium (Ti)** | - | 0.10 | Grain refiner. | | **Others (Each)** | - | 0.05 | - | | **Others (Total)** | - | 0.15 | - | **Key Point:** The addition of **Nickel (Ni)** is a defining characteristic of 2018 alloy. It forms stable compounds with iron and aluminum (e.g., Al₉FeNi), which help to retain strength at moderately elevated temperatures, making it suitable for applications like piston forgings. --- #### **2. Physical Properties** | Property | Value / Description | | :--- | :--- | | **Density** | 2.82 g/cm³ (0.102 lb/in³) | | **Melting Range** | ~ 507°C - 638°C (945°F - 1180°F) | | **Electrical Conductivity** | ~ 40-45% IACS (International Annealed Copper Standard) | | **Thermal Conductivity** | ~ 121 W/m·K | | **Coefficient of Thermal Expansion** | ~ 22.7 x 10⁻⁶/°C (20-100°C) | --- #### **3. Mechanical Properties (Typical for T61 Temper)** The T61 temper provides a high level of strength through artificial aging, which is more controlled and stable than natural aging (T4). | Temper | Tensile Strength | Yield Strength (0.2% Offset) | Elongation (% in 50mm) | Hardness | | :--- | :--- | :--- | :--- | :--- | | **2018-T61** | min. 405 MPa (59 ksi) | min. 310 MPa (45 ksi) | min. 10% | ~ 110-120 HB | *Note: The T61 temper is specifically designed to develop high strength and is commonly applied to forgings and other worked products.* --- #### **4. International Standards** 2018 Aluminum Alloy is recognized under several major international standards systems. | Standard System | Alloy Designation | Common Tempers | | :--- | :--- | :--- | | **ASTM (USA)** | **2018** | T61, T651 | | **AMS (Aerospace)** | **AMS 4122** | T61 (Forgings) | | **UNS (USA)** | **A92018** | - | | **JIS (Japan)** | **A2018** | T6 | *Note: In many standards, the "T6" temper (solution heat-treated and artificially aged) is specified, with "T61" often being a specific variant or a proprietary process used by manufacturers for forgings to achieve optimal properties.* --- #### **5. Product Applications** 2018-T61 is predominantly used in high-stress components, especially those that are forged and require stability at moderate temperatures. * **Aerospace Industry:** * Aircraft piston engines (e.g., pistons, cylinder heads) * Supercharger impellers * Other forged engine parts * **Automotive and Transportation (High-Performance):** * Forged racing pistons * High-strength connecting rods * Motorcycle and automotive drive components * **General Engineering:** * High-strength forgings for machinery * Gears and other heavily loaded components --- #### **6. Key Advantages & Considerations** * **Advantages:** * **High Strength:** The T61 temper provides excellent strength, superior to that of 2017-T4. * **Excellent Machinability:** It maintains the good machinability characteristic of the 2000-series copper-containing alloys. * **Good Elevated Temperature Performance:** The Ni-Fe additions provide better retention of strength at temperatures up to ~200°C (392°F) compared to alloys like 2017 or 2024. * **Suitable for Forging:** It is specifically designed and commonly used as a forging alloy. * **Considerations:** * **Poor Corrosion Resistance:** Like most high-copper aluminum alloys, it has very poor resistance to corrosion, especially in salt spray environments. It requires protective coatings such as anodizing or paint for most service conditions. * **Not Weldable:** It is generally considered non-weldable by common fusion welding techniques due to high susceptibility to hot cracking and loss of mechanical properties in the heat-affected zone. * **Limited Formability:** It is typically used in its final forged or machined shape and is not intended for severe forming operations. **Conclusion** 2018-T61 Aluminum Alloy is a specialized, high-performance forging alloy. Its unique composition, particularly the addition of nickel, makes it a superior choice for applications demanding high strength and stability under mechanical and thermal stress, such as in internal combustion engine components. While it shares the corrosion resistance and weldability challenges of other Al-Cu alloys, its targeted performance in forged parts secures its niche in the aerospace and high-performance automotive industries.

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 1527 gallon liquid totes Special package is available on request.