Aluminum 50/Nickel 50 Alloy,Nickel Aluminum Alloy,Ni50AI Alloy,E FORU

### **Nickel-Aluminum Alloy (50Ni/50Al, Ni₅₀Al₅₀) - Nickel Aluminide Intermetallic Compound** #### **Overview** The **Nickel-Aluminum Alloy with a nominal composition of 50% Nickel and 50% Aluminum** (typically expressed as **Ni₅₀Al₅₀** in atomic percentage) is not a conventional solid solution alloy but an **intermetallic compound** based on the NiAl phase. This material belongs to a class of advanced structural materials known for an exceptional combination of properties, including **high melting point, low density, excellent oxidation resistance, and high thermal conductivity**. Unlike traditional alloys where atoms are randomly distributed, intermetallic compounds like NiAl have an ordered crystal structure (B2, CsCl-type), which gives them high strength and stability at elevated temperatures. However, this ordered structure also typically results in low room-temperature ductility and fracture toughness, which has been a primary focus of research and development to make them viable for engineering applications. --- #### **Chemical Composition (Atomic % - Typical)** The composition is centered around the stoichiometric NiAl phase for optimal properties. | Element | Content (at.%) | Content (wt.%) (Approx.) | | :--- | :--- | :--- | | **Nickel (Ni)** | **45 - 55** | **~67 - 77** | | **Aluminum (Al)** | **Balance** | **~23 - 33** | | **Minor Additives** | (Y, Zr, Hf, Mo, Fe) | (< 0.5) | *Note: The stoichiometric NiAl phase exists over a range of compositions. Minor elements like Yttrium (Y) or Hafnium (Hf) are often added as dopants to improve the adherence of the protective alumina scale and enhance high-temperature creep resistance.* --- #### **Physical & Mechanical Properties** The following table outlines the key properties of the NiAl intermetallic compound. | Property | Value / Description | | :--- | :--- | | **Density** | **5.86 g/cm³** (Significantly lower than nickel-based superalloys) | | **Melting Point** | **1638 °C (2980 °F)** (Extremely high) | | **Crystal Structure** | Ordered B2 (Body-Centered Cubic) | | **Thermal Conductivity** | **~70 - 90 W/m·K** (at room temperature, much higher than superalloys) | | **Specific Heat** | ~500 J/kg·K | | **Coefficient of Thermal Expansion** | ~14.5 - 15.5 μm/m·°C (20-1000°C) | | **Elastic Modulus** | ~240 GPa (35 x 10⁶ psi) (High stiffness) | | **Tensile Strength (RT)** | ~200 - 500 MPa (Highly dependent on microstructure & processing) | | **Compressive Strength (RT)** | Very High | | **Room-Temperature Ductility** | **< 2%** (Typically brittle; can be improved via micro-alloying and processing) | | **High-Temperature Strength** | Excellent strength retention up to **1100 °C (2010 °F)** | | **Oxidation Resistance** | **Excellent.** Forms a continuous, protective Al₂O₃ (alumina) scale. | --- #### **Key Characteristics & Applications** **Key Characteristics:** 1. **High-Temperature Capability:** Exceptional strength-to-weight ratio and resistance to creep deformation at temperatures often exceeding those of conventional nickel-based superalloys. 2. **Outstanding Oxidation Resistance:** Its ability to form a stable, slow-growing alumina (Al₂O₃) scale makes it highly resistant to degradation in air and oxidizing atmospheres at high temperatures. 3. **High Thermal Conductivity:** This is a standout feature, being several times higher than that of superalloys. It allows for more efficient heat dissipation, reducing thermal gradients and associated stresses in components. 4. **Low Density:** Approximately 2/3 the density of typical superalloys, offering significant weight savings for rotating or high-speed components. 5. **Environmental Resistance:** Good resistance to corrosion in certain molten salts and metals. **Typical Applications:** NiAl and its composites are primarily used in demanding high-temperature, weight-sensitive applications, though often in specialized or developmental contexts due to fabrication challenges. * **Aerospace & Gas Turbine Engines:** * Potential candidate for **turbine blades** and **vanes** in the high-pressure section of jet engines. * **Stationary components** and heat shields within the hot gas path. * **Industrial Gas Turbines:** Similar components as in aerospace, where improved efficiency from higher operating temperatures and lower weight is targeted. * **Heat Treatment Industry:** Fixtures, trays, and radiant tubes for high-temperature furnaces. * **Advanced Composite Matrices:** The NiAl intermetallic is used as a matrix material for composites reinforced with ceramic fibers (e.g., Al₂O₃) to create ultra-high-temperature structural materials. * **Protective Coatings:** NiAl is a fundamental constituent in many bond coats for Thermal Barrier Coating (TBC) systems on superalloy components. --- #### **International Standards** As an advanced intermetallic material, Ni₅₀Al₅₀ is not typically covered by broad commercial material standards like ASTM for bulk forms in the same way conventional alloys are. Its specification is often driven by proprietary processing routes and specific application requirements. | Standard / System | Description | | :--- | :--- | | **Research & OEM Specifications** | Material properties and processing are primarily defined by **aerospace OEMs (e.g., GE, Rolls-Royce)** and **research institutions** for specific component applications. | | **AMS (Aerospace Material Spec.)** | No common, general AMS specification exists for bulk NiAl. Specifications are typically custom. | | **ISO** | No specific ISO standard for bulk NiAl intermetallic as a wrought product. | | **Processing Route** | Standards for **Powder Metallurgy (e.g., ASTM B595 for PM parts)** or **Investment Casting** may be referenced indirectly for the manufacturing process, but not for the material grade itself. | --- #### **Summary** In summary, the **50Ni/50Al (NiAl) intermetallic alloy** is a promising high-temperature structural material characterized by its **low density, very high melting point, outstanding oxidation resistance, and uniquely high thermal conductivity**. Its primary limitation—brittleness at room temperature—has been the subject of extensive material science research. While its use in bulk form is often specialized, its exceptional properties make it a critical material for the most advanced aerospace propulsion and power generation systems, both as a matrix for composites and as a coating material. Its standardization remains within the realm of specific engineering projects and proprietary OEM specifications rather than general international standards.

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 3210 gallon liquid totes Special package is available on request.