The effect of pulsed laser on the surface state of 3D-printed triply periodic structures in TiAl6V4 alloy

Abstract In this study, the effect of laser treatment on the surface of 3D-printed TiAl6V4 alloy with triply periodic structures was examined. As-printed and chemically etched samples served as references to assess surface changes. Microscopic analysis confirmed that laser treatment caused remelting and wave-like structures, while rapid cooling led to cracks through the new layer. Chemical and phase analyses showed the presence of TixOy (x = 1–2; y = 1–3) compounds, with variations between untreated and treated samples. Both modification methods removed un-sintered powder, but laser treatment preserved strut thickness, benefiting mechanical properties. In particular, the aim of the surface modification was to eliminate sintered particles to minimize the risk of detachment in in vivo applications, thereby enhancing implant reliability. The best mechanical performance was in untreated samples, with laser-treated ones showing only minor reduction. For example, a diamond-structured sample had a yield strength of 93 ± 2 MPa before treatment and 89 ± 3 MPa after. Additionally, surface hardness increased by about 60% post-treatment. Gyroid-structured samples showed superior strength, ductility, and compressive properties compared to diamond structures. Corrosion testing found no localized corrosion, confirming laser treatment did not degrade corrosion resistance. The metabolic activity of laser-treated materials remained above the 70% threshold, indicating cytocompatibility. Therefore, laser treatment holds promise for Ti-based 3D-printed implants.