Toward a sustainable laser powder bed fusion of Ti 6Al 4 V: Powder reuse and its effects on material properties during a single batch regime

Characterization, preparation, and reuse of metallic powders for laser powder bed fusion: a review

“…Since titanium is quite sensitive to oxygen, the reused powders tend to exhibit a higher oxygen content compared to that of virgin powders, as supported by various studies [181,183,196,203,242,245]. Although no change in powder composition is observed by EDS [203], the content of O and N elements in the reused powders increases [183,204,244].…”

“…It is observed that the O content of the powders increases from 0.128 wt% to 0.140 wt%, and the N content increases from 0.006 wt% to 0.019 wt% after reuse for 8 times [183]. An oxide layer with a thickness of about 20 nm is on the surface of powders which have been reused for 18 times [245] (figures 13(a-i) and (a-ii)). The increase in oxide thickness was also reported for Ti5553 [246], in which the thickness of hydroxylated mixed oxide composed of TiO 2 and Al 2 O 3 increased from (5.6 ± 0.7) nm to (8.3 ± 1.1) nm after repeated use.…”

“…To date, various titanium and titanium alloys have been extensively investigated via AM technologies, including the workhorse Ti6Al4V, β-type titanium alloy [238,239], and CP-Ti alloy [240]. In consideration of high cost of the titanium and titanium alloys, it is meaningful to understand the variation of powder characteristics and part properties of titanium and titanium alloys with powder reuse [181,183,196,203,204,[241][242][243][244][245].…”

“…The pick-up of oxygen and nitrogen of Ti and Ti alloy powders causes various evolution trends in the densification of printed parts among different researches [203,204,242,245,248]. The inconspicuous difference in densification for samples printed with virgin and reused powders is commonly observed.…”

“…(g) Charpy results. Reprinted from [245], Copyright (2023), with permission from Elsevier. number of reuse times increased.…”