Ti6Al4V (alpha-beta titanium, Grade 5) is the most widely used DMLS alloy because its combination of strength, weight, corrosion resistance, and biocompatibility covers the two highest-value applications in manufacturing: aerospace structures and medical implants.
Aerospace Ti6Al4V
Key requirements for aerospace titanium DMLS:
Specification: AMS 4999A (DMLS Ti6Al4V), AMS 6930 (powder chemistry spec) Quality system: AS9100D quality management; NADCAP accreditation for heat treatment Post-processing: Stress relief mandatory; HIP required for fatigue-critical flight hardware Testing: Tensile testing per specimen orientation (XY, XZ, Z) and heat treatment condition
Topology optimization of aerospace titanium brackets achieves 30–60% mass reduction versus machined equivalents at equivalent stiffness targets. Hydraulic manifolds, actuator housings, and duct fittings with internal channel geometry are prime candidates.
Medical Ti6Al4V ELI (Grade 23)
Key requirements for medical titanium DMLS:
Specification: ASTM F136 (Ti6Al4V ELI for surgical implants), ISO 5832-3 Quality system: ISO 13485 quality management; FDA 21 CFR Part 820 for devices Biocompatibility: ISO 10993-5 (cytotoxicity), ISO 10993-10 (sensitization) — inherently met by Ti6Al4V ELI at 99.5% density without residual monomer Osseointegration: Porous lattice surfaces (40–80% porosity, 400–700 µm cell) printed directly into implant contact surfaces promote bone ingrowth without press-fit anchoring
Post-Processing Comparison
| Step | Aerospace | Medical Implant |
|---|---|---|
| Stress relief | Required | Required |
| HIP | Required (fatigue-critical) | Required |
| CNC machining | Datum surfaces | Bearing surfaces, threads |
| Surface finish | Bead blast (Ra 1.6 µm) | Electropolish (Ra 0.4 µm) |
| NDT | X-ray CT, dye penetrant | CT for internal structure |