Ti-6Al-4V ELI (Grade 23)
Ti-6Al-4V ELI (Grade 23) is an Extra Low Interstitial (ELI) variant of Ti-6Al-4V, engineered for enhanced fracture toughness, corrosion resistance, and biocompatibility. It is the preferred titanium alloy for biomedical implants and high-performance aerospace components exposed to dynamic loads.
Through titanium 3D printing, Grade 23 enables the production of lightweight, structurally complex components including orthopedic implants, dental abutments, and aerospace brackets, offering optimized strength, fatigue life, and patient compatibility.
Ti-6Al-4V ELI Similar Grades Table
Country/Region | Standard | Grade or Designation |
|---|---|---|
USA | ASTM | Grade 23 |
USA | UNS | R56401 |
China | GB | TC4ELI |
ISO | ISO 5832-3 | Ti-6Al-4V ELI |
Ti-6Al-4V ELI Comprehensive Properties Table
Category | Property | Value |
|---|---|---|
Physical Properties | Density | 4.43 g/cm³ |
Melting Range | 1604–1660°C | |
Thermal Conductivity (20°C) | 6.6 W/(m·K) | |
Thermal Expansion (20–500°C) | 8.6 µm/(m·K) | |
Chemical Composition (%) | Titanium (Ti) | Balance |
Aluminum (Al) | 5.5–6.75 | |
Vanadium (V) | 3.5–4.5 | |
Oxygen (O) | ≤0.13 | |
Iron (Fe) | ≤0.25 | |
Mechanical Properties | Tensile Strength | ≥900 MPa |
Yield Strength (0.2%) | ≥825 MPa | |
Elongation at Break | ≥14% | |
Modulus of Elasticity | 110 GPa | |
Hardness (HRC) | 30–35 |
3D Printing Technology of Ti-6Al-4V ELI
Grade 23 is ideally suited for Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), and Electron Beam Melting (EBM), which preserve its biocompatibility and produce high-integrity structures suitable for load-bearing and implantable parts.
Applicable Process Table
Technology | Precision | Surface Quality | Mechanical Properties | Application Suitability |
|---|---|---|---|---|
SLM | ±0.05–0.2 mm | Excellent | Excellent | Biomedical, Aerospace |
DMLS | ±0.05–0.2 mm | Very Good | Excellent | Dental, Orthopedic, Consumer |
EBM | ±0.1–0.3 mm | Good | Very Good | Structural, Large-Scale Medical |
Ti-6Al-4V ELI 3D Printing Process Selection Principles
SLM is optimal for medical implants, dental fixtures, and aerospace connectors requiring tight tolerances (±0.05–0.2 mm) and clean internal structures with surface roughness Ra 5–10 µm.
DMLS is widely adopted for complex geometries in biomedical devices and mechanical parts that require excellent surface finish and high mechanical uniformity.
EBM supports large-scale medical structures such as femoral stems or orthopedic plates with high build rates and moderate precision (±0.1–0.3 mm).
Ti-6Al-4V ELI 3D Printing Key Challenges and Solutions
Residual stress and thermal distortion are common challenges. Implementing support structures and HIP processing at 920–950°C and 100–150 MPa enhances fatigue life and dimensional stability.
Porosity, especially critical in implants, is minimized through optimized scan strategies (laser power: 250–350 W; scan speed: 600–900 mm/s) and HIP, achieving >99.9% density.
Surface finish (Ra 8–15 µm) may impair biocompatibility and wear resistance. Electropolishing and CNC machining reduce surface roughness to Ra 0.4–1.0 µm, meeting ISO 5832-3 standards for implants.
To preserve oxygen limits critical to ELI grade, powder storage and printing must maintain O₂ < 200 ppm and humidity < 5% RH.
Industry Application Scenarios and Cases
Ti-6Al-4V ELI is widely used in:
Medical: Hip stems, spinal cages, dental implants, trauma plates.
Aerospace: Structural brackets, engine attachments, lightweight stiffeners.
Consumer Products: Biocompatible wearable devices and precision hardware.
A recent orthopedic application used SLM to produce customized femoral implants, reducing lead time by 60% and improving patient-specific fit and bone integration due to controlled porosity and superior surface finish.
FAQs
Why is Ti-6Al-4V ELI preferred for medical implant 3D printing?
How does Grade 23 differ from standard Ti-6Al-4V in performance and applications?
What post-processing steps are needed to meet implant-grade surface requirements?
What are the common challenges in printing Ti-6Al-4V ELI and how are they resolved?
Which industries benefit most from 3D printed Ti-6Al-4V ELI components?
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