Alloy 909,Incoloy 909,UNS N19909,E FORU

### **Alloy 909 / Incoloy® 909 / UNS N19909** #### **Low Thermal Expansion, High-Strength Superalloy** **Overview** Alloy 909 (commonly known by its trade name **Incoloy® 909**) is a low thermal expansion, iron-nickel-cobalt-base superalloy designed for high-strength applications requiring dimensional stability over a wide temperature range. Its key characteristic is a controlled low coefficient of thermal expansion (CTE) combined with excellent mechanical properties and good fatigue resistance up to 650°C (1200°F). This unique combination makes it ideal for critical components in aerospace and gas turbine engines where tight tolerances must be maintained from ambient to operating temperatures. --- ### **Chemical Composition (Weight %)** The typical chemical composition of Alloy 909 is outlined below. The balance is Iron (Fe). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Nickel (Ni)** | 38.0 - 41.0 | Austenite matrix former, controls thermal expansion. | | **Cobalt (Co)** | 13.0 - 16.0 | Strengthens matrix, contributes to thermal stability. | | **Columbium (Cb) + Tantalum (Ta)** | 4.5 - 5.5 | Primary strengthening via precipitation of gamma prime/gamma double prime phases. | | **Titanium (Ti)** | 1.3 - 1.8 | Forms strengthening precipitates (Ni₃Ti). | | **Silicon (Si)** | 0.30 - 0.50 | Deoxidizer, improves oxidation resistance. | | **Aluminum (Al)** | 0.15 max | Controlled to prevent formation of unwanted phases. | | **Carbon (C)** | 0.04 max | Affects strength and fabricability. | | **Manganese (Mn)** | 0.50 max | Controls sulfur content, improves hot workability. | | **Sulfur (S)** | 0.015 max | Impurity, controlled to prevent hot shortness. | | **Boron (B)** | 0.012 max | Enhances creep strength and grain boundary cohesion. | | **Copper (Cu)** | 0.50 max | Impurity, controlled. | | **Phosphorus (P)** | 0.015 max | Impurity, controlled to maintain ductility. | *Note: Columbium (Cb) is also commonly referred to as Niobium (Nb).* --- ### **Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.23 g/cm³ (0.297 lb/in³) | | **Melting Range** | ~ 1370 °C (2500 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 400°C (68 - 752°F): **7.6 x 10⁻⁶/°C** (4.2 x 10⁻⁶/°F)
20 - 540°C (68 - 1004°F): **8.5 x 10⁻⁶/°C** (4.7 x 10⁻⁶/°F) | | **Thermal Conductivity** | 14.9 W/m·K (103 Btu·in/hr·ft²·°F) at 100°C (212°F) | | **Specific Heat** | 460 J/kg·K (0.11 Btu/lb·°F) at 100°C (212°F) | | **Electrical Resistivity** | 1.05 μΩ·m at 21°C (70°F) | | **Modulus of Elasticity (Young's Modulus)** | 148 GPa (21.5 x 10⁶ psi) at 21°C (70°F) | | **Magnetic Permeability** | Essentially non-magnetic in annealed condition. | --- ### **Mechanical Properties (Typical for Annealed Condition)** | Property | At Room Temperature | At 540°C (1000°F) | | :--- | :--- | :--- | | **Tensile Strength** | 1100 MPa (160 ksi) | 860 MPa (125 ksi) | | **Yield Strength (0.2% Offset)** | 860 MPa (125 ksi) | 760 MPa (110 ksi) | | **Elongation (in 50 mm)** | 15% | 15% | | **Reduction of Area** | 45% | 45% | | **Hardness (Rockwell C)** | 32 HRC | - | *Note: Properties can be significantly enhanced through aging heat treatments, which precipitate strengthening phases.* --- ### **International Standards** Alloy 909 is covered by several international material standards: * **ASTM:** B 753 (Standard Specification for Thermostat Metal Sheet and Strip) * **AMS:** AMS 7721 (Bar, Forgings, and Rings), AMS 7722 (Sheet, Strip, and Plate) * **UNS:** N19909 * **ISO:** Not as widely standardized as other superalloys, but specifications are often agreed upon between customer and supplier based on ASTM or AMS requirements. --- ### **Product Applications** The unique properties of Alloy 909 make it indispensable in high-precision, high-temperature environments: 1. **Aerospace & Gas Turbine Engines:** * **Seals and Rings:** Critical for maintaining tight clearances between rotating and stationary parts (e.g., turbine shrouds, casing seals). * **Struts and Support Structures:** Where dimensional stability under thermal cycling is paramount. 2. **Automotive Turbochargers:** * **Turbine Shafts:** Its ability to maintain strength and resist thermal fatigue at high temperatures makes it suitable for high-performance turbocharger components. 3. **Precision Instruments and Measurement Devices:** * **Laser Components:** Used in mounts and frames to ensure optical alignment remains constant. * **Bimetallic Thermostats:** The low CTE is engineered against other metals to create precise thermal actuators. 4. **Nuclear Reactors:** * **Core Components:** Used in specific instrumentation and structural components where low expansion and radiation resistance are beneficial. --- ### **Key Characteristics & Advantages** * **Controlled Low Thermal Expansion:** Maintains dimensions from cryogenic temperatures to over 500°C. * **High Strength-to-Weight Ratio:** Excellent mechanical properties at elevated temperatures. * **Good Fatigue and Creep Resistance:** Suitable for long-term, high-stress applications. * **Good Fabricability:** Can be machined, welded (using matching filler metal), and formed with standard techniques, though it is a strong, hard material. **Disclaimer:** *Incoloy® is a registered trademark of Special Metals Corporation, a PCC company. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier.*

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 1650 gallon liquid totes Special package is available on request.