The thermal-history difference does most of the work
EBM builds inside a chamber held at ~700 °C; L-PBF builds on a build plate that's often near room temperature. That single difference cascades into almost every other column of the matrix: lower thermal gradients give EBM lower residual stress and a lamellar α/β microstructure that more closely resembles wrought Ti-6Al-4V; the higher beam power gives EBM 3–5× the bulk deposition rate; but the hot, dusty chamber gives EBM its coarse as-built surface and its weaker feature resolution.
Where EBM wins outright
Medical implants, large titanium frames, and any Ti part where surface roughness is going to be machined off anyway. The combination of low residual stress, near-wrought microstructure, and 3× the build rate is hard to beat once finish is decoupled from the as-built state.
Where L-PBF wins outright
Anything with sub-millimeter features, thin walls, lattice structures, or as-built surface requirements. The qualification path is also broader: more OEMs, more parameter sets, more coupon data in MMPDS-2024.
Frequently asked questions
Is the EBM coupon base big enough for A-basis allowables?
For HIP'd EBM Ti-6Al-4V the data set is sufficient for typical values and program-specific A-basis derivations. The public MMPDS-2024 A-basis row is still tighter for L-PBF than for EBM because of the wider OEM coverage.
Sources
- Tammas-Williams, S. et al. (2018). The effectiveness of HIP on EBM Ti-6Al-4V. Acta Mater. 145.
- Murr, L. E. et al. (2012). Microstructures and mechanical properties of EBM and L-PBF Ti-6Al-4V. J. Mech. Behav. Biomed. Mater. 12.