MP35N Nickel/Cobalt/Chromium/Molybdenum Alloy,nickel-cobalt based alloy,MP35N alloy，1

### **Introduction to MP35N® (UNS R30035) Nickel-Cobalt Based Alloy** **MP35N®** is a unique, ultra-high-strength, corrosion-resistant nickel-cobalt-chromium-molybdenum alloy. Its name stands for **M**ulti-**P**hase alloy, age-hardenable to **35**0 ksi (thousands of pounds per square inch) tensile strength. Unlike many other high-performance alloys that derive strength from a nickel or iron matrix, MP35N's exceptional properties are achieved through a specialized thermomechanical processing route that induces a **multiphase strengthening mechanism**. The alloy's key characteristic is its combination of **ultimate strength** (one of the highest among any commercial alloy), **excellent toughness**, and **outstanding corrosion resistance** in severe environments, including saltwater and hydrogen sulfide. It is also fully **biocompatible**, making it suitable for medical implants. --- ### **Chemical Composition (Weight %, typical)** The composition is balanced to enable its unique strengthening mechanism and provide corrosion resistance. | Element | Minimum | Maximum | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | **Balance** | | Forms the primary austenitic (FCC) matrix. | | **Cobalt (Co)** | 33.0 | 37.0 | Stabilizes the matrix and enables the formation of a hexagonal close-packed (HCP) phase during processing. | | **Chromium (Cr)** | 19.0 | 21.0 | Provides exceptional resistance to corrosion and oxidation. | | **Molybdenum (Mo)** | 9.0 | 10.5 | Enhances strength and resistance to pitting and crevice corrosion. | | **Titanium (Ti)** | 0.9 | 1.2 | Contributes to age-hardening. | | **Iron (Fe)** | - | 1.0 | Kept low to ensure corrosion performance. | | **Manganese (Mn)** | - | 0.15 | - | | **Silicon (Si)** | - | 0.15 | - | | **Carbon (C)** | - | 0.025 | - | | **Boron (B)** | 0.005 | 0.015 | Strengthens grain boundaries. | ***Key Differentiator:*** The near-equal parts of Nickel and Cobalt are fundamental to its multiphase strengthening mechanism. --- ### **Physical Properties (Typical)** * **Density:** 8.43 g/cm³ (0.305 lb/in³) * **Melting Range:** ~1330 - 1440 °C (~2430 - 2620 °F) * **Thermal Expansion Coefficient:** 12.2 μm/m·°C (20-400°C) * **Thermal Conductivity:** 13.0 W/m·K at 100°C * **Modulus of Elasticity (Young's Modulus):** 232 GPa (33.7 x 10⁶ psi) at 21°C * **Magnetic Permeability:** Typically <1.005 (essentially non-magnetic) --- ### **Mechanical Properties (Typical)** Properties are highly dependent on the processing (cold work + aging) condition. The following are for high-strength wire/bar. | Condition | Tensile Strength | Yield Strength (0.2% Offset) | Elongation | | :--- | :--- | :--- | :--- | | **Annealed** | ~ 1000 MPa (145 ksi) | ~ 600 MPa (87 ksi) | ~ 50% | | **Cold Worked + Aged (High Strength)** | **> 1790 MPa (260 ksi)** | **> 1725 MPa (250 ksi)** | ≥ 8% | *The alloy is capable of achieving yield strengths exceeding 2400 MPa (350 ksi), which is the origin of its name.* --- ### **Key Characteristics and Product Applications** #### **Key Characteristics:** 1. **Ultra-High Strength & Toughness:** Possesses an unparalleled combination of strength and fracture toughness, even at cryogenic temperatures. 2. **Exceptional Corrosion Resistance:** Resists pitting, crevice corrosion, and stress corrosion cracking (SCC) in environments like saltwater, sour gas (H₂S), and chlorides. Its performance often surpasses that of many stainless steels and nickel alloys. 3. **Multiphase Strengthening Mechanism:** Strength is achieved by cold working the austenitic (FCC) structure, which transforms a portion of it to a martensitic (HCP) phase. A subsequent aging step further strengthens the material. 4. **Biocompatibility:** Meets the requirements of ISO 5832-6 and ASTM F562, making it suitable for long-term implantable medical devices. 5. **Non-Magnetic:** Maintains its non-magnetic character even after severe cold working. #### **Primary Applications:** MP35N is used in the most demanding applications where failure is not an option. * **Medical Devices:** * **Implantable Components:** Hip and knee joint replacements, bone fixation plates, and screws. * **Cardiovascular Devices:** Coronary stents, heart valve components, guidewires, and pacemaker leads. * **Aerospace & Defense:** * **Fasteners:** High-strength bolts, nuts, and rivets for critical airframe and engine applications. * **Springs and Bearings** * **Landing Gear Components** * **Oil & Gas:** * **Downhole Tools:** Components for logging tools, packers, and other equipment in sour gas wells. * **Valve Trim and Shafts** * **Marine Engineering:** * Fasteners and components for subsea systems exposed to seawater. --- ### **International Standards** MP35N is covered by several key specifications, particularly in the medical and aerospace sectors. | Product Form | Standard | Designation / Notes | | :--- | :--- | :--- | | **General Material** | **UNS** | **R30035** | | **Bar, Wire, Strip (Medical)** | **ASTM F562** | UNS R30035 | The primary specification for wrought material used in medical implants. | | **Bar, Wire, Strip (Aerospace)** | **AMS 5844, 5845, 5846, 5847** | MP35N Alloy | Various specifications for different cold-worked and aged conditions (e.g., AMS 5844 for 260 ksi min tensile strength). | | **Seamless Tube** | AMS 5848 | MP35N Alloy | - | | **Forgings** | AMS 5849 | MP35N Alloy | - | | **European Medical** | **ISO 5832-6** | Wrought cobalt-nickel-chromium-molybdenum alloy | - | **Note:** "MP35N" is a registered trademark of **SPS Technologies, Inc.** (now part of **Precision Castparts Corp.**). It is a premium, high-performance alloy whose processing is critical to achieving its unique properties. Consultation with the manufacturer for specific application requirements is essential.

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 3269 gallon liquid totes Special package is available on request.