Aerospace structures
Airframe fittings, engine mounts, landing gear components, fasteners, hydraulic tubing — anywhere a steel part would be too heavy and an aluminum part too weak.
Titanium · Grade 5 · UNS R56400
Ti-6Al-4V
The most widely used titanium alloy in the world. Outstanding strength-to-weight, biocompatible, corrosion-resistant — and 50%+ of all titanium production goes into Ti-6Al-4V because it just works.
UTS
950 MPa
Density
4.43 g/cc
Modulus
113.8 GPa
Mach.
22 /100
When to use
Pick titanium when weight matters and strength can’t be sacrificed.
Titanium 6Al-4V hits a sweet spot of strength, low density, fatigue life, and biocompatibility that no other production alloy matches. It’s the default for aerospace structural parts, medical implants, racing components, and high-end mechanical hardware.
The catch: it’s expensive (roughly 4–8× the cost of stainless per pound), tough on tools, and unforgiving of bad machining practice. Don’t spec it just because the customer’s last drawing did — confirm you actually need its property profile.
Ti-6Al-4V's specific strength is why aerospace pays for it. Steel reaches similar absolute strength but with ~2× the weight.
Strengths
Common applications.
- Strength-to-weightAmong the best of any production metal. ~45% lighter than steel at similar UTS.
- BiocompatibleInert in the body — the standard for orthopedic, dental, and surgical implants.
- Corrosion-resistantForms a passive oxide layer that resists seawater, chlorides, and most acids.
- Fatigue performanceExcellent endurance limit — ideal for cyclically loaded aerospace structures.
- High-temp capableRated to ~316 °C (600 °F) for long-term service; short-term excursions can run higher.
Trade-offs
What you pay for it.
- Stock costBar stock roughly 4–8× the price of stainless per pound. Expect material to be 30–60% of finished part cost.
- Machining costSlow cutting speeds + tool wear → cycle times often 2–3× longer than 4140 steel.
- GallingWill gall against itself and other metals. Threading and fasteners need special treatment.
- HeatLow thermal conductivity (6.7 W/m·K) — heat goes into the tool, not the chip.
- Fire riskFine chips and dust are flammable. Coolant and chip control are critical.
Specs
Mechanical, physical & chemical data.
Typical values for annealed Ti-6Al-4V bar stock per ASTM B348. Solution-treated and aged (STA) condition reaches higher strength at the cost of some ductility.
Mechanical
Properties (annealed)
| Ultimate tensile strength | 950 MPa (138 ksi) |
|---|---|
| Yield strength (0.2% offset) | 880 MPa (128 ksi) |
| Elongation at break | 14% |
| Reduction of area | 36% |
| Modulus of elasticity | 113.8 GPa |
| Shear modulus | 44 GPa |
| Poisson's ratio | 0.342 |
| Hardness | 36 HRC (≈334 HV) |
| Fatigue strength10⁷ cycles, R = -1 | 510 MPa |
Source: ASM Handbook Vol. 2; MatWeb. Properties for solution-treated and aged (STA) condition: UTS ≈1170 MPa, YS ≈1100 MPa.
Physical & thermal
Properties at room temp
| Density | 4.43 g/cc (0.160 lb/in³) |
|---|---|
| Melting point | 1604–1660 °C |
| Beta transus | 995 °C (1820 °F) |
| Specific heat | 0.526 J/g·°C |
| Thermal conductivityLow — drives the machining challenge | 6.7 W/m·K |
| CTE (0–100 °C) | 8.6 µm/m·°C |
| Electrical resistivity | 1.78 µΩ·m |
| Magnetic permeability | Non-magnetic |
Compare thermal conductivity to aluminum (167 W/m·K) — heat lingers at the cutting edge.
Composition
Chemistry, weight %
| Aluminum (Al) | 5.50 – 6.75 |
|---|---|
| Vanadium (V) | 3.50 – 4.50 |
| Iron (Fe) | 0.40 max |
| Oxygen (O) | 0.20 max |
| Carbon (C) | 0.08 max |
| Nitrogen (N) | 0.05 max |
| Hydrogen (H) | 0.0125 max |
| Titanium (Ti) | balance |
Ti-6Al-4V ELI (Grade 23) caps O at 0.13% and N at 0.05% — preferred for medical implants and fracture-critical aerospace parts.
Specifications
Common purchase specs.
When ordering, reference the spec that matches your application. Aerospace and medical buyers typically require certified material test reports (CMTR) traceable to mill lot.
ASTM B348
Bar, billet — Grade 5
AMS 4928
Bars, rings, forgings — annealed
AMS 4965
Forgings — solution-treated and aged
AMS 4967
Bars, wire — annealed
AMS 6931
Bars, forgings — annealed
MIL-T-9046
Sheet, strip, plate
ASTM F136
Surgical implant grade (Grade 23 / ELI)
ISO 5832-3
Implants for surgery — wrought Ti-6Al-4V
Machining
Machining considerations.
Ti-6Al-4V is unforgiving. The right approach: low surface speed, aggressive feed, sharp tools, generous high-pressure coolant, and never let the tool dwell.
Cutting speed
150–250 SFM carbide milling, 150–260 SFM carbide turning. HSS runs far slower.
Feed rate
Aggressive — keeps the edge cutting fresh material instead of rubbing.
Depth of cut
Variable for finishing. Constant pressure on the tool prevents work-hardening.
Tooling
Carbide grades C-2 / C-3 standard. PVD/CVD-coated for production.
Coolant
Flood, ideally high-pressure (1000+ psi) through-spindle. Chip evacuation matters.
No dwell
Stopping the feed mid-cut work-hardens the surface and ruins finish.
Climb milling
Strongly preferred. Conventional milling rubs and creates heat.
Sharp edges
Worn tools generate heat that goes into the tool, not the chip. Replace early.
Applications
Where Ti-6Al-4V earns its cost.
Medical implants
Hip & knee prostheses, bone screws, dental implants, spinal hardware. Ti-6Al-4V ELI (Grade 23) is the standard for implant-grade requirements.
Energy & defense
Submarine valves, deep-sea enclosures, missile components. The alloy resists chloride pitting that destroys most stainless in seawater.
Compare
Related materials.
Need a Ti-6Al-4V part made?
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