Optimization of Laser Based-Powder Bed Fusion Parameters for Controlled Porosity in Titanium Alloy Components.

Area of Science:

• Materials Science and Engineering
• Additive Manufacturing
• Titanium Alloys

Background:

• Laser-based powder bed fusion (LB-PBF) is a key additive manufacturing technology for producing complex, high-performance parts.
• Tailoring material properties, beyond geometric complexity, offers significant potential for technical innovation.
• Ti6Al4V titanium alloy is widely used due to its excellent mechanical properties.

Purpose of the Study:

• To optimize LB-PBF process parameters for Ti6Al4V titanium alloy parts with controlled porosity.
• To investigate the impact of process parameters on porosity, surface characteristics, and atomic structure.
• To explore the potential for creating parts with tailored porosity for advanced applications.

Main Methods:

• Fabrication of cuboid and lamellar Ti6Al4V samples using LB-PBF.
• Systematic variation of laser power, hatch distance, and layer thickness via a full factorial Design of Experiments.
• Characterization of porosity, surface roughness, waviness, morphology, and surface area.
• Analysis of atomic structure and nanometric porosity using small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS).

Main Results:

• Fine control over porosity and surface characteristics of Ti6Al4V was achieved within specific LB-PBF process windows.
• Pores were predominantly closed, even in thin-walled structures.
• Surface roughness was identified as the primary determinant of surface area.
• Lamellar samples, produced from single scan tracks, exhibited an order-of-magnitude increase in surface area and pore volume.

Conclusions:

• LB-PBF process parameters can be effectively optimized to control porosity and surface properties in Ti6Al4V.
• The study provides a foundation for producing Ti6Al4V parts with tailored porosity, particularly through lamellar structures.
• The findings pave the way for advanced applications requiring optimized pore structures in titanium alloys.