Nickelvac X-750 Nickel Superalloy, UNS N07750; AMS 5667, 5668, 5669, 5670, 5671. MIL-N-24114, ASTM B 637,E FORU

### **Product Introduction: Nickelvac® X-750 Nickel-Chromium Superalloy (UNS N07750)** **Nickelvac X-750** is a precipitation-hardenable nickel-chromium superalloy known for its high strength and excellent corrosion resistance at temperatures up to 1300°F (700°C) and beyond. Its combination of outstanding mechanical properties, good fabricability, and resistance to oxidation and creep makes it a highly reliable material for demanding applications in aerospace, industrial, and nuclear environments. The alloy derives its strength from the precipitation of gamma prime [γ'] phase (Ni₃(Al, Ti)) during a controlled aging heat treatment. This mechanism allows it to maintain high strength levels significantly superior to standard nickel-chromium alloys like Alloy 600. --- #### **1. Chemical Composition (Weight %)** The typical chemical composition of Nickelvac X-750 per AMS 5667 and other relevant specifications is as follows: | Element | Content (%) | Element | Content (%) | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | ≥ 70.0 | **Aluminum (Al)** | 0.40 - 1.00 | | **Chromium (Cr)** | 14.00 - 17.00 | **Titanium (Ti)** | 2.25 - 2.75 | | **Iron (Fe)** | 5.00 - 9.00 | **Niobium + Tantalum (Nb+Ta)** | 0.70 - 1.20 | | **Manganese (Mn)**| ≤ 1.00 | **Silicon (Si)** | ≤ 0.50 | | **Copper (Cu)** | ≤ 0.50 | **Sulfur (S)** | ≤ 0.01 | | **Carbon (C)** | ≤ 0.08 | **Phosphorus (P)** | ≤ 0.015 | | **Cobalt (Co)** | ≤ 1.00* | **Boron (B)** | 0.006 max | *Cobalt is typically controlled to a low level, but specific customer or application requirements may vary. **Key Microstructure:** The primary strengthening phase is gamma prime (γ'), Ni₃(Al, Ti), which is precipitated during a two-step aging heat treatment. The addition of Niobium also contributes to strengthening. --- #### **2. Physical Properties** Typical physical properties for X-750 alloy are provided below. | Property | Metric Units | Imperial Units | | :--- | :--- | :--- | | **Density** | 8.28 g/cm³ | 0.299 lb/in³ | | **Melting Range** | ~1390 - 1430 °C | ~2530 - 2610 °F | | **Specific Heat (20°C)** | 431 J/kg·K | 0.103 Btu/lb·°F | | **Thermal Conductivity (20°C)** | 11.7 W/m·K | 81 Btu·in/hr·ft²·°F | | **Mean Coefficient of Thermal Expansion (20-100°C)** | 12.8 μm/m·°C | 7.1 μin/in·°F | | **Modulus of Elasticity (Tensile)** | 214 GPa | 31 x 10⁶ psi | | **Electrical Resistivity** | 1.22 μΩ·m | - | --- #### **3. Mechanical Properties (Typical for AMS 5667 - Bar & Forging)** Mechanical properties are highly dependent on the specific heat treatment condition. The most common condition for high-strength applications is **Solution Annealed + Double Aged**. **Common Heat Treatment:** * **Solution Treat:** 1800°F ± 25°F (982°C ± 14°C), followed by rapid cooling. * **Aging:** 1300°F (705°C) for 20 hours, air cool + 1150°F (621°C) for 20 hours, air cool. **Typical Room Temperature Properties (After Solution Anneal & Double Aging):** | Property | Value (Typical) | | :--- | :--- | | **Tensile Strength** | 1200 MPa (174 ksi) min | | **Yield Strength (0.2% Offset)** | 830 MPa (120 ksi) min | | **Elongation (in 4D)** | 20% min | | **Reduction of Area** | 24% min | *Note: These are typical minimum values; actual properties can vary with product form and specific heat treatment.* --- #### **4. International Standards & Specifications** Nickelvac X-750 is one of the most standardized superalloys, covered by numerous specifications for different product forms and applications. **Aerospace Material Specifications (AMS - SAE International):** * **AMS 5667:** Bars, forgings, and rings. (Solution Annealed and aged) * **AMS 5668:** Forging stock. (Solution Annealed) * **AMS 5669:** Sheet, strip, and plate. (Solution Annealed and precipitation heat treated) * **AMS 5670:** Wire. (Solution Annealed and precipitation heat treated) * **AMS 5671:** Spring wire. (Solution Annealed, cold drawn, and precipitation heat treated) **Other Key Standards:** * **UNS:** N07750 * **MIL Spec:** **MIL-N-24114** (Bars, wire, forgings, and rings for aerospace vehicles) * **ASTM:** * **ASTM B637**: Standard Specification for Precipitation-Hardening Nickel Alloy Bars, Forgings, and Forging Stock for High-Temperature Service. * Other ASTM specs cover different forms (e.g., B637 for bar, B163 for tube). * **AECMA/EN:** 2.4669 * **ISO:** 9724 (Nickel alloy bars) * **ASME:** SB-637 (For pressure vessel and nuclear components) --- #### **5. Product Applications** Nickelvac X-750's unique properties make it suitable for a vast range of critical applications. * **Aerospace & Gas Turbines:** * Turbine blades and vanes * Engine disks and rotors * Bolts, fasteners, and springs * Thrust reverser components * Formed sheet parts for hot sections * **Nuclear Industry:** * Reactor core components (e.g., spacer grids, guide tubes, springs) * Fuel assembly hardware * **Industrial & General Engineering:** * High-temperature springs and bellows * Forming tools and die inserts * Heat treating fixtures and trays * Critical fasteners for high-pressure/temperature systems --- #### **Summary of Key Advantages** * **High Strength-to-Weight Ratio:** Excellent strength maintained from cryogenic temperatures up to ~1300°F (700°C). * **Excellent Creep & Stress Rupture Properties:** Performs reliably under sustained loads at high temperatures. * **Good Corrosion Resistance:** Resists oxidation and corrosion in a variety of environments, similar to Alloy 600. * **Outstanding Fatigue Resistance:** Withstands cyclic loading, making it ideal for rotating parts and springs. * **Proven Reliability:** A long-standing, well-understood alloy with an extensive service history in the most demanding fields. **Disclaimer:** The information provided is for reference purposes. Specific properties and performance are dependent on the manufacturing process, heat treatment, and final product form. For critical applications, always consult the official material specifications and the alloy producer's data sheets.

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 3127 gallon liquid totes Special package is available on request.