Ti-6Al-4V ELI (Grade 23)
About Ti-6Al-4V ELI Superalloy
Name and Equivalent Name
Ti-6Al-4V ELI, or Grade 23, conforms to international standards: UNS R56401, ASTM B348, DIN/EN 3.7165, AMS 4907, and ISO 5832-2.
Ti-6Al-4V ELI Basic Introduction
Ti-6Al-4V ELI is a variant of the widely used Ti-6Al-4V alloy, offering extra low interstitial elements, such as nitrogen and carbon, to improve ductility and fracture toughness. It is preferred for critical applications requiring enhanced mechanical performance under stress, such as aerospace and medical implants.
This superalloy combines high strength, corrosion resistance, and excellent biocompatibility. It maintains structural integrity under cyclic loading and can withstand operating temperatures up to 400°C. Typical applications include surgical implants, airframes, and pressure vessels.
Alternative Superalloys of Ti-6Al-4V ELI
Alternative materials to Ti-6Al-4V ELI include Ti-6Al-4V (Grade 5) for applications requiring less stringent toughness. Ti-3Al-2.5Sn offers improved weldability and thermal stability. Nickel-based superalloys, such as Inconel 718, are used when higher temperature resistance is needed.
For specialized applications, titanium grades like Ti-5Al-2.5Sn provide better oxidation resistance. In medical fields, Co-Cr alloys may be considered alternatives due to their wear resistance, although they lack the biocompatibility of Ti-6Al-4V ELI.
Ti-6Al-4V ELI Design Intention
The primary design intention of Ti-6Al-4V ELI is to enhance mechanical properties by limiting interstitial elements such as nitrogen and carbon. This ensures higher fracture toughness and ductility, which is essential for medical implants and components exposed to dynamic loads.
The alloy was specifically developed to meet the stringent requirements of aerospace and biomedical applications, ensuring excellent fatigue strength, corrosion resistance, and biocompatibility. Its enhanced properties make it suitable for environments where safety and durability are paramount.
Ti-6Al-4V ELI Chemical Composition
The chemical composition of Ti-6Al-4V ELI ensures optimal strength, lightweight properties, and improved fracture toughness by controlling interstitial impurities.
Element | Content (wt%) |
|---|---|
Aluminum (Al) | 5.5 – 6.5 |
Vanadium (V) | 3.5 – 4.5 |
Carbon (C) | ≤ 0.08 |
Iron (Fe) | ≤ 0.3 |
Nitrogen (N) | ≤ 0.05 |
Ti-6Al-4V ELI Physical Properties
Ti-6Al-4V ELI offers a favorable balance of density, thermal conductivity, and elastic modulus, contributing to its lightweight, durable nature.
Property | Value |
|---|---|
Density | 4.43 g/cm³ |
Melting Point | 1604°C |
Thermal Conductivity | 6.7 W/(m·K) |
Elastic Modulus | 110 – 115 GPa |
Metallographic Structure of Ti-6Al-4V ELI Superalloy
The metallographic structure of Ti-6Al-4V ELI is a refined alpha-beta structure. The alloy's low interstitial elements improve fracture toughness, ensuring durability under mechanical stress. The alpha phase, primarily stabilized by aluminum, contributes to strength, while the beta phase, stabilized by vanadium, provides enhanced ductility.
Ti-6Al-4V ELI's structure ensures excellent performance in fatigue-critical applications, such as implants and airframes. This structure also allows post-processing treatments like annealing to tailor the alloy’s mechanical properties for specific applications.
Ti-6Al-4V ELI Mechanical Properties
Ti-6Al-4V ELI offers excellent mechanical properties, maintaining strength and ductility under high temperatures and cyclic loads.
Property | Value |
|---|---|
Tensile Strength | 860 – 910 MPa |
Yield Strength | 795 MPa |
Hardness | 30 – 32 HRC |
Elongation | 15 – 18% |
Key Features of Ti-6Al-4V ELI Superalloy
Enhanced Biocompatibility Ti-6Al-4V ELI is widely used in the medical industry for implants due to its excellent biocompatibility and low rejection rate, ensuring long-term stability in the human body.
Superior Fracture Toughness The alloy’s extra low interstitial elements enhance fracture toughness, making it ideal for components exposed to high dynamic loads and cyclic stress.
High Fatigue Strength Ti-6Al-4V ELI exhibits exceptional fatigue resistance, ensuring long-lasting performance in aerospace components subjected to repeated mechanical stress.
Corrosion Resistance This alloy withstands harsh environments, including saltwater and chemical exposure, making it suitable for marine and chemical processing applications.
Thermal Stability Ti-6Al-4V ELI maintains mechanical properties up to 400°C, providing reliability in aerospace and industrial applications.
Ti-6Al-4V ELI Superalloy’s Machinability
Vacuum Investment Casting: Ti-6Al-4V ELI is suitable for Vacuum Investment Casting due to its ability to retain mechanical properties with minimal porosity, offering precision for aerospace and biomedical components.
Single Crystal Casting: Single Crystal Casting is not ideal for Ti-6Al-4V ELI as the alloy is more suitable for equiaxed microstructures than single-phase crystal growth applications.
Equiaxed Crystal Casting: Ti-6Al-4V ELI performs well in Equiaxed Crystal Casting, delivering uniform grains that enhance fatigue strength and fracture resistance, ideal for structural applications.
Superalloy Directional Casting: Superalloy Directional Casting is less common for Ti-6Al-4V ELI since the alloy's properties align better with equiaxed forms, prioritizing toughness over directional creep resistance.
Powder Metallurgy Turbine Disc: Ti-6Al-4V ELI is not typically used for Powder Metallurgy Turbine Disc applications due to limited high-temperature performance compared to nickel-based alloys.
Superalloy Precision Forging: Superalloy Precision Forging is well-suited for Ti-6Al-4V ELI, optimizing its mechanical properties for aerospace and medical components through refined grain structures.
Superalloy 3D Printing: Ti-6Al-4V ELI is widely used in Superalloy 3D Printing due to its excellent printability, enabling complex geometries for medical and aerospace applications.
CNC Machining: Ti-6Al-4V ELI requires precise tool selection for CNC Machining, but it offers excellent surface finishes and dimensional accuracy, which is crucial for medical implants.
Superalloy Welding: Superalloy Welding of Ti-6Al-4V ELI demands advanced techniques to avoid cracking, but the alloy’s weldability makes it suitable for aerospace and medical assembly.
Hot Isostatic Pressing (HIP): Hot Isostatic Pressing (HIP) eliminates internal voids in Ti-6Al-4V ELI, improving critical components' fatigue life and mechanical properties.
Ti-6Al-4V ELI Superalloy Applications
Aerospace and Aviation: In Aerospace and Aviation, Ti-6Al-4V ELI is used for airframes, fasteners, and engine components due to its lightweight nature and high fatigue resistance.
Power Generation: In power generation, Ti-6Al-4V ELI is applied to turbine blades and heat exchangers, leveraging its moderate temperature tolerance and corrosion resistance.
Oil and Gas: Ti-6Al-4V ELI is deployed in the Oil and Gas industry for valves, pipelines, and offshore equipment, offering excellent corrosion resistance in harsh environments.
Energy: Due to its high strength-to-weight ratio, energy systems incorporate Ti-6Al-4V ELI for structural components in renewable technologies, such as wind turbines.
Marine: The Marine industry benefits from Ti-6Al-4V ELI for propeller shafts and hull components, where corrosion resistance and durability are essential.
Mining: In Mining, Ti-6Al-4V ELI is used in pump housings, shafts, and drill bits, offering wear resistance and reliability under extreme conditions.
Automotive: Automotive applications include lightweight components like exhaust systems and valve springs, improving fuel efficiency and performance.
Chemical Processing: In Chemical Processing, Ti-6Al-4V ELI is used for reactor vessels and heat exchangers, providing corrosion resistance against aggressive chemicals.
Pharmaceutical and Food: Ti-6Al-4V ELI serves the Pharmaceutical and Food industries by delivering biocompatible components like mixers and valves that comply with hygiene standards.
Military and Defense: In Military and Defense, the alloy is utilized in armor plating and aircraft components, ensuring durability and lightweight performance.
Nuclear: The Nuclear sector employs Ti-6Al-4V ELI for radiation-resistant parts and reactor components exposed to corrosive environments.
When to Choose Ti-6Al-4V ELI Superalloy
Custom superalloy parts made from Ti-6Al-4V ELI are ideal for biocompatibility and mechanical strength. This alloy is preferred for medical implants, aerospace fasteners, and chemical reactors. It is best used in applications where fatigue and corrosion resistance are essential, and weight reduction is critical. Ti-6Al-4V ELI offers reliable performance in dynamic and high-stress environments for industries such as aerospace and energy. With its ability to maintain properties at elevated temperatures and under cyclic loads, Ti-6Al-4V ELI is a versatile choice for complex engineering challenges.
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