Effect of powder characteristics on production of oxide dispersion strengthened Fe 14Cr steel by laser powder bed fusion

In order to assess the potentialities of additive manufacturing in nuclear industry, Oxide Dispersion Strengthened (ODS) Fe[sbnd]14Cr steels are produced by laser powder bed fusion (L-PBF). Such materials are currently manufactured by milling a Fe[sbnd]14Cr atomized powder with Y2O3 and TiH2 powders. The resulting powder has a non-spherical shape being coarser than powders typically used in L-PBF equipment. The influence of powder characteristics on the processability of ODS Fe[sbnd]14Cr by L-PBF are studied in details. Four different powders are used. These powders differ from size, morphology and chemical composition. Finer is the powder; wider is the process range to obtain dense samples. This phenomenon could be mitigated by transferring an amount of energy superior to 110 J.mm−3. The presence of yttrium and titanium gives columnar microstructure for ODS samples, whereas Fe[sbnd]14Cr samples have stirred microstructure. Titanium and yttrium form oxides, which enlarge the melt pool and induce columnar growth. © 2019 Elsevier B.V.