Oxidation in Reused Powder Bed Fusion Additive Manufacturing Ti-6Al-4V Feedstock: A Brief Review

Unmelted titanium alloy (Ti-6Al-4V) feedstock powder oxidizes during powder bed fusion additive manufacturing. This review focuses on the potential effect variations of the powder reuse method may have on the oxidation rate over multiple builds in both electron beam and laser powder bed fusion processes. No correlation of the oxidation rate based on the powder reuse method has been observed, but significant variation in the oxidation rate has been observed between reuse methods. The authors feel that these results highlight a need for better reporting of the details of the powder reuse method (e.g., mixing) to appropriately assess the potential for the reuse method to affect the oxidation rate. Recommendations for powder reuse and details for a higher level of reporting are provided. Multiple instances of variable oxidation rate within a given experiment have been observed. The implications of this heterogeneity on mechanical property variability might be significant.