Reusability of Ti-6Al-4V powder in laser powder bed fusion: Influence on powder morphology, oxygen uptake, and mechanical properties

Abstract

The reusability of Ti-6Al-4V powder in laser powder bed fusion (L-PBF) processes is essential for achieving economic efficiency and maintaining consistent product quality. While powder reuse offers clear cost benefits, it also raises concerns about preserving material quality and consistency across multiple build cycles. This study, therefore, investigates the effects of repeated powder reuse on key parameters, including powder morphology, oxygen uptake, and mechanical properties. The results demonstrate that the repeated reuse of the powder results in a decrease in satellite particles and an increase in particle deformation. Oxygen content progressively increases with each cycle; however, smooth particles maintain relatively stable oxygen levels, whereas rough particles exhibit a more pronounced rise in oxygen content. Mechanical testing shows that as oxygen levels increase, tensile strength improves, yet elongation decreases. This observed increase in strength can be partially attributed to oxygen-induced phase transformations, where localized oxygen enrichment promotes the formation of the face-centered cubic (FCC) β phase, contributing to material strengthening. These findings emphasize the importance of optimizing powder reuse strategies, particularly in controlling oxygen levels, to achieve the optimal balance between strength and ductility in high-quality material properties.