Page 161 - MSAM-4-3

Materials Science in Additive Manufacturing L-PBF Ti-10Ta-2Nb-2Zr: Microstructure and Strength

features of the gyroid lattice. The gyroid represents a triply in space and eliminates sharp angles or abrupt cross-
periodic minimal surface with constant mean curvature, sectional changes characteristic of other topologies. This
which provides the most uniform material distribution leads to more stable heat transfer conditions during the
L-PBF process, minimization of stress concentrators, and
Table 5. Compression mechanical properties of lattice and consequently, enhanced reproducibility of mechanical
solid structures properties among different specimens.
Structure Elastic modulus (GPa) Yield strength (MPa) 3.6.2. Triply periodic minimal surface microstructure
Schwarz 9.2±1.1 207.9±4.8 analysis
Gyroid 9.2±0.5 198.4±2.1 Microstructural analysis of the etched surface of the
Split 9.7±0.4 193.6±5.9 gyroid structure revealed a characteristic microstructural
Solid 52.2±8.4 539.3±23.3 gradient from the periphery to the center of lattice
elements (Figure 12). The observed transition from fine
acicular structure at the edges to coarser lamellar structure
in the central regions reflects differences in crystallization
conditions during L-PBF. Peripheral regions in contact
with pores are characterized by higher cooling rates due to
efficient heat dissipation through the gaseous medium and
surrounding powder, which leads to the formation of fine
acicular α’-martensitic structure. In the central regions of
lattice elements, where heat dissipation is less intensive,
slower cooling occurs, promoting the growth of coarser α’
plates.
The observed microstructural gradient in TPMS
struts reflects the complex thermal conditions during
L-PBF processing of thin structural elements. Peripheral
regions experience higher cooling rates due to efficient
Figure 11. Compression mechanical properties of lattice structures heat dissipation through the surrounding pore space and
A B

C D

Figure 12. Optical microscope images of a gyroid-type structure. (A) AAA, scale bar: 250 μm; magnification: ×10; (B) BBB, scale bar: 250 μm; magnification:
×20; (C) CCC, scale bar: 50 μm; magnification: ×50; (D) DDD, scale bar: 50 μm; magnification: ×50

Volume 4 Issue 3 (2025) 13 doi: 10.36922/MSAM025220044