Effect of powder characteristics on production of oxide dispersion strengthened Fe[sbnd]14Cr steel by laser powder bed fusion
Résumé
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.
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