Haynes X-750 Nickel Alloy,Haynes X-750 (UNS No. N07750) alloy,Alloy X-750，1

### **Introduction to Haynes® X-750 (UNS N07750) Nickel-Based Superalloy** **Haynes® X-750** (commonly known as **Alloy X-750**) is a precipitation-hardenable nickel-chromium alloy known for its high strength and excellent corrosion resistance at temperatures up to 1300°F (700°C). It is derived from and shares a similar base composition with the iconic Alloy 600 (Nickel 600), but with key additions of aluminum, titanium, and niobium that allow it to be strengthened by a precipitation hardening heat treatment. This process forms the coherent gamma prime [γ'] phase (Ni₃(Al, Ti)), giving Alloy X-750 significantly higher yield and tensile strength than its solution-strengthened counterparts, making it a premier choice for high-stress mechanical applications in aerospace and industrial environments. --- ### **Chemical Composition (Weight %, typical)** The composition is optimized for precipitation hardening while maintaining good corrosion resistance. | Element | Minimum | Maximum | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | **Balance** | | Forms the austenitic matrix. | | **Chromium (Cr)** | 14.0 | 17.0 | Provides resistance to oxidation and corrosion. | | **Iron (Fe)** | 5.0 | 9.0 | Balances the structure and cost. | | **Titanium (Ti)** | 2.25 | 2.75 | **Primary gamma' former:** Combines with Ni to form the main strengthening phase, Ni₃(Al, Ti). | | **Aluminum (Al)** | 0.40 | 1.00 | **Gamma' former:** Co-precipitates with Ti to form the strengthening phase. | | **Niobium (Nb)** | 0.70 | 1.20 | Forms the stable Ni₃Nb (gamma prime or eta) phase, contributing to strength and stabilization. | | **Cobalt (Co)** | - | 1.00 | - | | **Manganese (Mn)** | - | 1.00 | - | | **Silicon (Si)** | - | 0.50 | - | | **Copper (Cu)** | - | 0.50 | - | | **Carbon (C)** | - | 0.08 | Forms carbides for grain boundary strength. | | **Sulfur (S)** | - | 0.01 | - | --- ### **Physical Properties (Typical)** * **Density:** 8.28 g/cm³ (0.299 lb/in³) * **Melting Range:** 1395 - 1425 °C (2540 - 2600 °F) * **Thermal Expansion Coefficient:** 13.1 μm/m·°C (20-100°C) * **Thermal Conductivity:** 14.0 W/m·K at 100°C * **Modulus of Elasticity (Young's Modulus):** 214 GPa (31 x 10⁶ psi) at 21°C --- ### **Mechanical Properties (Typical)** Properties are highly dependent on the specific heat treatment condition. A common aging treatment (AH) is shown below. **Room Temperature Properties (After Solution Annealing and Aging - Condition AH):** * **Tensile Strength:** ≥ 1140 MPa (165 ksi) * **Yield Strength (0.2% Offset):** ≥ 795 MPa (115 ksi) * **Elongation:** ≥ 20% ***High-Temperature Strength:*** Alloy X-750 retains excellent strength at elevated temperatures. For example, it maintains a 1000-hour rupture strength of approximately **310 MPa (45 ksi) at 1300°F (704°C)**. --- ### **Key Characteristics and Product Applications** #### **Key Characteristics:** 1. **High Strength-to-Weight Ratio:** Offers exceptional strength, making it ideal for critical structural components. 2. **Excellent Creep Rupture Strength:** Performs reliably under sustained load at high temperatures. 3. **Good Oxidation & Corrosion Resistance:** Suitable for use in a variety of corrosive atmospheres, similar to Alloy 600. 4. **Precipitation Hardenable:** Its properties are achieved through a specific sequence of heat treatments (Solution Treat + Aging), allowing for flexibility in manufacturing. #### **Primary Applications:** Alloy X-750 is a workhorse in industries requiring high strength and reliability. * **Aerospace & Jet Engines:** * **Gas Turbine Blades, Disks, and Rotors** * **Engine Mounts and Fasteners** * **Bolt and Stud Assemblies** * **Spacers and Seals** * **Nuclear Industry:** * **Spacer Grids and Spring Clips** for nuclear fuel assemblies. * **Industrial Gas Turbines:** * **Turbine Buckets (Blades) and Wheels** * **Other Applications:** * High-strength fasteners, extrusion dies, bellows, and springs for high-temperature service. --- ### **International Standards** Alloy X-750 is covered by numerous long-established and well-defined specifications. | Product Form | Standard | Designation | Notes | | :--- | :--- | :--- | :--- | | **Bar, Forgings, Ring** | **AMS 5667** | Alloy X-750 | The primary aerospace specification for bars and forgings (Solution and Precipitation Treated). | | **Sheet, Strip, Plate** | **AMS 5542** | Alloy X-750 | Standard for sheet, strip, and plate forms. | | **Wire, Spring Quality** | **AMS 5698** | Alloy X-750 | Specification for high-strength wire, often used for springs and fasteners. | | **Bar, Billet, Forgings** | ASTM B637 | UNS N07750 | Standard Specification for Precipitation-Hardening Nickel Alloy. | | **Welding Consumables** | AWS A5.14 | **ERNiCrFe-7** | Commonly used filler metal for welding X-750 to itself or other nickel alloys. | **Note:** "Haynes" is a registered trademark of **Haynes International, Inc.** Alloy X-750 is also widely produced and supplied under the **INCONEL® X-750** trademark (Special Metals Corporation). The specific heat treatment condition (e.g., AH, HTH, SHT) is critical and must be specified during procurement to ensure the material meets the mechanical property requirements for the intended application.

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 3265 gallon liquid totes Special package is available on request.