Titanium for Implantable Medical Devices
Ti 6Al/4V ELI sheet has found application in
medical implants owing to its excellent biocompatibility, high strength, and MRI compatibility.
In the cold rolled and annealed temper the material will not exhibit a continuous alpha network at prior beta grain boundaries or a continuous alpha case layer on the surface. Owing to the alloy’s high strength and low ductility, it is difficult to cold draw into finished shapes. Hot forming has been found to be effective.
Any post cold work annealing must be done in vacuum to prevent oxygen, nitrogen and hydrogen contamination which will result in reduced formability. In addition, the annealing temperature must not exceed the beta transus temperature of the alloy, approximately 980°C.
Available Sizes
Ti 6Al/4V ELI is available from AMETEK Specialty Metal Products as sheet product from 0.005” to 0.020”, widths up to 6.0” and lengths up to 18”.
The material conforms to ASTM F 136, ASTM B 265 grade 23 and UNS R56401.
Chemical Composition
| Titanium Grade 23 Chemical Composition (Weight %) |
| Aluminum |
5.5 – 6.5 |
| Vanadium |
3.5 – 4.5 |
| Iron |
0.25 max |
| Carbon |
0.08 max |
| Nitrogen |
0.05 max |
| Oxygen |
0.13 max |
| Hydrogen |
0.015 max |
* The measured elongation will be less as thickness decreases to 0.005” and less
Material over 0.032” thick limited to hydrogen content of 0.012% max.
Mechanical Properties
| Titanium Grade 23 Mechanical Properties |
|
ANNEALED
|
| Ultimate Tensile Strength |
125,000 PSI |
| Yield Strength (.2% Offset) |
115,000 PSI |
| Elongation in 2” * |
10% min* |
| Electrical Resistivity |
178 micro-ohm-cm |
These values may be adjusted by control of process variables – consult Ametek SMP
for desired values
Physical Properties
| Titanium Grade 23 Physical Properties |
| Density |
0.16 lb/in3
|
| Melting Point (Approx.) |
1650°C |
| Electrical Resistivity @ R.T. |
168 Microhm·cm |
Thermal Expansion Coefficient
(20 to 100°C)
(20 to 315°C) |
8.6 X 10-6/°C
9.2 X 10-6/°C |
| Thermal Conductivity @ R.T. |
6.7 W/m·K |
| Magnetic Attraction |
None |
Typical values to guide alloy selection but are not a guarantee of minimum or maximum