Effective Ti-6Al-4V Powder Recycling in LPBF Additive Manufacturing Considering Powder History

Laser powder bed fusion (LPBF) is an outstanding additive manufacturing (AM) technology that can enable both complicated geometries and desired mechanical properties in high-value components. However, the process reliability and cost have been the obstacles to the extensive industrial adoptions of LPBF. This work aims to develop a powder recycling procedure to reduce production cost and minimize process uncertainties due to powder degradation. We used a recycle index (R) to reuse Ti-6Al-4V powder through 10 production cycles. Using this recycle index is more reasonable than simply replying on recycle numbers as it incorporates the powder usage history. A recycling procedure with simple virgin powder top-up can effectively mitigate powder degradation and maintain stable powder properties, chemical compositions, and tensile properties. The experimental finding points to a sustainable recycling strategy of Ti alloy powders with minimal material waste and without noticeable detriment to observed mechanical performance through LPBF production cycles.