Nickel 55/Titanium 45 Shape Memory Alloy，1

### **Nickel-Titanium Shape Memory Alloy (Ni₅₅Ti₄₅) - Nitinol** #### **Overview** **Nickel-Titanium Shape Memory Alloy (Ni₅₅Ti₄₅)**, commercially known as **Nitinol** (Nickel Titanium Naval Ordnance Laboratory), is a remarkable intermetallic compound that exhibits two unique properties: the **shape memory effect** and **superelasticity** (pseudoelasticity). This near-equiatomic alloy can "remember" its original shape and return to it when heated above its transformation temperature, while also demonstrating exceptional elasticity (up to 8% recoverable strain) in its superelastic state. These properties make it one of the most important functional materials in modern engineering and medical applications. --- #### **Chemical Composition (Atomic % / Weight %)** | Element | Atomic % | Weight % (Approx.) | |---------|-------------|-----------| | **Nickel (Ni)** | **54.5-55.5%** | **~54.5-55.5%** | | **Titanium (Ti)** | **Balance** | **~44.5-45.5%** | | **Carbon (C)** | **≤ 0.05%** | **Impurity control** | | **Oxygen (O)** | **≤ 0.05%** | **Impurity control** | | **Cobalt (Co)** | **0-0.05%** | **Transformation temperature adjustment** | *Note: The transformation temperature is highly sensitive to composition variations - a 0.1% change in Ni content can alter the transformation temperature by ~10°C.* --- #### **Physical & Mechanical Properties** | Property | Austenite Phase | Martensite Phase | |----------|----------------|------------------| | **Density** | **6.45 g/cm³** | **6.40 g/cm³** | | **Melting Point** | **~1310°C** (2390°F) | **~1310°C** (2390°F) | | **Transformation Temperature** | **-100°C to +100°C** (adjustable via composition) | | | **Thermal Conductivity** | **10-18 W/m·K** | **8.5-10 W/m·K** | | **Electrical Resistivity** | **80-100 μΩ·cm** | **70-80 μΩ·cm** | | **Specific Heat** | **320-460 J/kg·K** | **320-460 J/kg·K** | | **Young's Modulus** | **75-83 GPa** | **28-41 GPa** | | **Tensile Strength** | **800-1100 MPa** | **~100-800 MPa** | | **Elongation** | **15-20%** | **30-50%** | | **Recoverable Strain** | **Up to 8%** (superelastic) | **Up to 8%** (shape memory) | | **Fatigue Strength** | **Excellent** (rotating beam: ~500 MPa) | | --- #### **Transformation Characteristics** | Parameter | Typical Range | |-----------|---------------| | **Austenite Start (As)** | **-100°C to +100°C** | | **Austenite Finish (Af)** | **Adjustable via composition and processing** | | **Martensite Start (Ms)** | **Typically 20-50°C below As** | | **Martensite Finish (Mf)** | **Typically 20-50°C below Ms** | | **Hysteresis (As-Ms)** | **20-50°C** | | **Transformation Enthalpy** | **~28 J/g** | --- #### **Key Characteristics & Applications** **Key Characteristics:** - **Shape Memory Effect**: Ability to recover predetermined shape upon heating - **Superelasticity**: Extraordinary elasticity (up to 8% strain recovery) - **Biocompatibility**: Excellent for medical implant applications - **Damping Capacity**: High vibration and shock absorption - **Wear Resistance**: Good resistance to abrasive wear - **Corrosion Resistance**: Comparable to titanium alloys **Typical Applications:** **Medical Devices:** - **Stents**: Vascular, esophageal, and biliary stents - **Orthodontic Archwires**: Continuous light force delivery - **Guidewires**: Kink-resistant surgical instruments - **Bone Plates and Screws**: Self-compressing orthopedic implants - **Surgical Tools**: Flexible and steerable instruments **Industrial Applications:** - **Couplings**: Pipe couplings for aerospace and marine - **Actuators**: Thermal actuators for automotive and aerospace - **Valves**: Thermal control valves - **Robotics**: Artificial muscles and flexible mechanisms - **Consumer Products**: Eyeglass frames, cellular phone antennas **Aerospace Applications:** - **Deployable Structures**: Satellite antennas, solar panels - **Vibration Dampers**: Helicopter rotor systems - **Morphing Structures**: Adaptive wing surfaces --- #### **International Standards & Specifications** | Standard | Designation | Description | |----------|-------------|-------------| | **ASTM** | **F2063** | Standard specification for wrought nickel-titanium shape memory alloys | | **ASTM** | **F2005** | Terminology for nickel-titanium shape memory alloys | | **ISO** | **12405** | Implants for surgery - nickel-titanium shape memory alloy | | **USP** | **Class VI** | United States Pharmacopeia biocompatibility testing | | **FDA** | **510(k)** | Medical device clearance requirements | --- #### **Manufacturing & Processing** **Available Forms:** - **Bar and Rod**: 0.1 mm to 100 mm diameter - **Wire**: 0.05 mm to 5 mm diameter - **Tube**: For stent manufacturing - **Sheet and Strip**: 0.1 mm to 5 mm thickness - **Custom Shapes**: For specific applications **Processing Guidelines:** - **Hot Working**: 700-900°C (avoid oxidation) - **Cold Working**: With intermediate anneals - **Heat Treatment**: 400-600°C for shape setting - **Surface Treatment**: Electropolishing, passivation - **Joining**: Laser welding, brazing with special techniques --- #### **Quality Control & Testing** - **Chemical Analysis**: ICP, combustion analysis for interstitial elements - **Transformation Temperature**: DSC, bend and free recovery tests - **Mechanical Testing**: Tensile, fatigue, and durability testing - **Microstructural Analysis**: SEM, TEM for phase identification - **Biocompatibility**: Cytotoxicity, sensitization, implantation tests - **Functional Testing**: Actuation cycles, strain recovery testing --- #### **Summary** **Nickel 55/Titanium 45 Shape Memory Alloy (Nitinol)** represents a paradigm-shifting functional material that has revolutionized numerous fields, particularly medical device technology. Its unique combination of shape memory and superelastic properties, coupled with excellent biocompatibility and corrosion resistance, has enabled innovative solutions in minimally invasive surgery, orthodontics, and cardiovascular medicine. The alloy's ability to perform mechanical work through thermal activation and its extraordinary elasticity continue to inspire new applications across aerospace, automotive, and consumer product industries. While requiring specialized manufacturing and processing techniques, Nitinol's unique capabilities ensure its continued growth and development as a key advanced material for 21st-century engineering challenges.

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 3224 gallon liquid totes Special package is available on request.