Ti Grade 5 and Ti Grade 5 ELI are the same alloy: Ti6Al4V. Their aluminium and vanadium contents are almost identical. The difference is in how far the interstitial elements are limited. ELI stands for exactly that — “Extra Low Interstitial”.
Oxygen and iron down
According to our datasheets, standard Grade 5 has oxygen at ≤0.20% and iron at ≤0.20%. In the ELI version oxygen falls to ≤0.13% and hydrogen to ≤0.0125%; the iron limit is given as ≤0.25%. The upper limit for aluminium is also pulled back from 6.75% to 6.50%.
Oxygen sits in the titanium lattice and hardens the material, but it also makes it more brittle. Lowering the oxygen means giving up some strength — the yield strength of ELI is ≥760 MPa against ≥830 MPa for standard Grade 5. What is gained in return is fracture toughness and resistance to crack propagation.
That trade-off becomes critical in two areas. The first is cryogenic applications: at very low temperatures standard Grade 5 becomes brittle while ELI keeps its ductility. The second is medical implants: in a part that will carry load inside the body for decades, crack tolerance is worth more than a few hundred MPa of strength.
Comparison in numbers
| PROPERTY | Ti Grade 5 | Ti Grade 5 ELI |
|---|---|---|
| Aluminium (Al) | 5.50 – 6.75% | 5.50 – 6.50% |
| Vanadium (V) | 3.50 – 4.50% | 3.50 – 4.50% |
| Oxygen (O) | ≤ 0.20% | ≤ 0.13% |
| Iron (Fe) | ≤ 0.20% | ≤ 0.25% |
| Hydrogen (H) | ≤ 0.015% | ≤ 0.0125% |
| Nitrogen (N) | ≤ 0.05% | ≤ 0.05% |
| Carbon (C) | ≤ 0.08% | ≤ 0.08% |
| Tensile strength Rm | ≥ 895 N/mm² | ≥ 825 N/mm² |
| Yield strength Rp0.2 | ≥ 830 N/mm² | ≥ 760 N/mm² |
| Elongation | ≥ 10% | ≥ 10% |
| Density | ≥ 4.43 g/cm³ | ≥ 4.45 g/cm³ |
| Modulus of elasticity | 114 kN/mm² | 114 kN/mm² |
| UNS | R56400 | R56401 |
| AMS / ASTM | AMS 4928 · AMS 4911 | ASTM F136 · ASTM B348 |
Values are taken from our product datasheets; section thickness and the applied heat treatment regime change the result.
Which one, and when?
Ti Grade 5 is sufficient — aircraft structural parts, engine components, fasteners, sports and racing equipment, general high-strength titanium applications. It is easier to source and lower in cost.
Ti Grade 5 ELI is required — hip, knee and spinal implants, surgical screws and plates, cryogenic pressure vessels, liquid hydrogen and oxygen tanks, deep-sea pressure hulls. If the specification calls out ASTM F136 — and for medical implants it nearly always does — standard Grade 5 is not an acceptable substitute.
Neighbouring grades
For a comparison with the pure titanium grades, see our Ti Grade 2 – Grade 5 article. For softer and harder pure titanium options there are Ti Grade 1 and Ti Grade 4.
Technical datasheets
Ti Grade 5 — chemical composition, mechanical values, standard equivalents
Ti Grade 5 ELI — chemical composition, mechanical values, standard equivalents
Both grades are supplied to order in round bar, flat bar, plate, sheet, pipe and forged forms. Contact us for a quotation.