Additive manufacturing of continuous wave and pulsed wave L-PBF Ti64 thin cross sections

Abstract

The additive manufacturing of titanium alloys, particularly Ti–6Al–4V (Ti64), via Laser Powder Bed Fusion (L-PBF) techniques, has garnered significant attention due to the potential for creating complex geometries and reducing material waste. This study compares the Continuous Wave (CW) and Pulsed Wave (PW) L-PBF methods in fabricating thin Ti64 struts, essential for biomedical applications such as lattice-structured implants. The feasibility of manufacturing cylindrical struts with diameters ranging from 0.1 to 1.0 mm and angles of inclination between 10° and 90° has been explored. Findings indicate that CW L-PBF produces finer struts with consistent cross sections but tends to generate higher surface roughness due to heat accumulation and sintered particles. In contrast, in this case, PW L-PBF achieves better retention of the designed angles and smoother surfaces at higher inclinations but struggles with strut dimensions at lower angles due to contour scanning which helps improve shape retention at high angle of inclinations. Microstructural analysis reveals that PW L-PBF results in a bit finer α′ martensitic needles, attributed to higher cooling rates, generated due to the pulsed laser mode, while CW L-PBF shows coarser structures due to continuous heat input resulting in a prolonged thermal cycling effect.