TC4 ELI / Ti-6Al-4V ELI (Grade 23) Titanium Alloy

TC4 ELI (Extra Low Interstitial) is the refined variant of TC4 / Ti-6Al-4V, corresponding to international ASTM Grade 23 / UNS R56401 / ASTM F136 (medical) / AMS 4919. By restricting oxygen, iron and hydrogen, it offers markedly better fracture toughness, ductility and cryogenic / damage-tolerance performance at a small strength penalty, making it the standard choice for medical implants and critical aerospace structures.

Overview

• Material: TC4 ELI — Ti-6Al-4V ELI (α+β)
• International equivalents: ASTM Gr.23 / UNS R56401 / ASTM F136 (surgical implant) / AMS 4919
• Available forms: Bar, plate, sheet, wire, forgings and fasteners

Chemical Composition (wt%)

Other elements: each ≤ 0.10 %, total ≤ 0.40 %. ELI tightens Fe, O and H limits versus standard Grade 5.

Physical Properties

Mechanical Properties (annealed)

Retains good mechanical properties at cryogenic temperatures.

Key Features

• Excellent biocompatibility — no adverse reaction with human tissue;
• Good strength and toughness to carry service loads;
• Strong corrosion resistance in many media;
• Superior cryogenic and damage-tolerance properties versus standard Grade 5;
• Good ductility and formability.

Fabrication & Heat Treatment

• Melting: typically triple-melted from Grade 0 / 0A sponge titanium, with tight control of interstitial elements (Fe, O, H).
• Hot working: forged, rolled or extruded at 850–1000 °C with controlled heating.
• Cold working: cold rolled and cold drawn; intermediate annealing at approx. 650–700 °C.
• Welding: TIG welding after thorough cleaning, with suitable parameters and inert-gas shielding.
• Annealing: 700–800 °C for 1–2 h, air cool.
• Solution treatment & ageing: solution treat at 900–950 °C then rapid cool; age at 500–550 °C to raise strength.

Typical Applications

• Medical: artificial joints, bone-fixation devices, dental implants and cranial-reconstruction materials (per ASTM F136 / ISO 5832-3);
• Aerospace: spars, frames, wing panels and engine components requiring high damage tolerance;
• Marine: structures and seawater piping operating at low temperature in seawater service.

For detailed datasheets, mill certificates (EN 10204 3.1) or inquiries on specific sizes and tolerances, please contact our sales & engineering team.