Laser Powder Bed Fusion Additive Manufacturing of Oxide Dispersion Strengthened Steel Using Gas Atomized Reaction Synthesis Powder

Horn, Timothy; Rock, Christopher; Kaoumi, Djamel; Anderson, Iver E.; White, Emma; Prost, Tim; Rieken, Joel; Saptarshi, Sourabh; Schoell, Ryan; deJong, Matthew M.; Timmins, Sarah; Napolitano, Ralph E.; Zhang, Dalong; Darsell, Jens T.

doi:10.2139/ssrn.3985835

Cited by 2 publications

(8 citation statements)

References 48 publications

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“…35 More recent studies have experimented with varying the LPBF chamber atmosphere or the powder composition. 19,[36][37][38][39] While the reported data are promising, these studies highlight the need for tight control over the relative stoichiometry between oxygen and oxide formers within the LPBF melt pool. However, they are not conclusive with respect to how tightly the atmosphere must be controlled or the influence of subtle variations in local oxygen content on the oxide size, density distribution, and homogeneity.…”

Section: Introductionmentioning

confidence: 92%

“…All samples were fabricated with 10 mm 9 10 mm scan patches with an angle of rotation at 45°. 38 These patches were shifted from layer to layer by 2.5 mm. The layer thickness for the study was fixed at 0.025 mm, and the beam power was fixed at 95 W. 44 The hatch spacing was varied in discrete steps (0.03 mm, 0.05 mm, and 0.08 mm).…”

Section: Lpbf Sample Fabricationmentioning

confidence: 99%

“…Previous studies using similar ferritic steel GARS compositions identified Y as elemental Y at the grain boundaries, in solution in the matrix, or as a stable intermetallic compound Y 2 Fe 17 . 38,[40][41][42] The labeled boxes in Fig. 3a refer to regions inspected with high-angle annular dark-field (HAADF) imaging and EDS maps of Fe, Cr, Ti, Y, and O in Fig.…”

Section: Powder Characterizationmentioning

confidence: 99%

“…39 In our study, the observation of spherical oxides in the fabricated solid indicates that the intermetallic The oxide size and density in this study are comparable to what has been reported for recent AM processing of ODS steels which has been compiled in detail in recent reviews. 38 Among the smallest reported oxide sizes and highest oxide densities for LPBF are those produced by in situ synthesis with reactive atmospheres, but these data, while compelling, are insufficient to draw broad conclusions regarding an optimal processing pathway and further studies are needed. Horn et al recently reported an average oxide size of 12.2 nm and density of 3.4 9 10 21 /m 3 produced with LPBF in an atmosphere of Ar + 5 wt.% O 2 .…”

Section: Characterization Of Lpbf Consolidated 14ywtmentioning

confidence: 99%

“…These data showed a trend of decreasing oxide size and increasing oxide density with increasing atmospheric oxygen up to 5% by weight. 38 In the present study, additional oxygen was supplied during atomization to increase the oxygen content in the shell of the powder. It is hypothesized that the oxide shells will provide the appropriate stoichiometry of oxygen to react with Y and Ti in the powder to form nano-scale Y 2 Ti 2 O 7 pyrochlore oxides without additional oxygen in the LPBF atmosphere.…”

Section: Introductionmentioning

confidence: 99%

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Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Saptarshi

deJong

Rock

et al. 2022

JOM

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Laser powder bed fusion (LPBF) additive manufacturing (AM) is a promising route for the fabrication of oxide dispersion strengthened (ODS) steels. In this study, 14YWT ferritic steel powders were produced by gas atomization reaction synthesis (GARS). The rapid solidification resulted in the formation of stable, Y-containing intermetallic Y2Fe17 on the interior of the powder and a stable Cr-rich oxide surface. The GARS powders were consolidated with LPBF. Process parameter maps identified a stable process window resulting in a relative density of 99.8%. Transmission electron microscopy and high-energy x-ray diffraction demonstrated that during LPBF, the stable phases in the powder dissociated in the liquid melt pool and reacted to form a high density (1.7 × 1020/m3) of homogeneously distributed Ti2Y2O7 pyrochlore dispersoids ranging from 17 to 57 nm. The use of GARS powder bypasses the mechanical alloying step typically required to produce ODS feedstock. Preliminary mechanical tests demonstrated an ultimate tensile and yield strength of 474 MPa and 312 MPa, respectively.

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Section: Introductionmentioning

confidence: 92%

Section: Lpbf Sample Fabricationmentioning

confidence: 99%

Section: Powder Characterizationmentioning

confidence: 99%

Section: Characterization Of Lpbf Consolidated 14ywtmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Saptarshi

deJong

Rock

et al. 2022

JOM

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Impact of zirconia slurry in steel powder on melt pool characteristics in laser powder bed fusion

Davis

Nelson

Crane

2022

RPJ

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Purpose dding dopants to a powder bed could be a cost-effective method for spatially varying the material properties in laser powder bed fusion (LPBF) or for evaluating new materials and processing relationships. However, these additions may impact the selection of processing parameters. Furthermore, these impacts may be different when depositing nanoparticles into the powder bed than when the same composition is incorporated into the powder particles as by ball milling of powders or mixing similarly sized powders. This study aims to measure the changes in the single bead characteristics with laser power, laser scan speed, laser spot size and quantity of zirconia nanoparticle dopant added to SS 316 L powder. Design/methodology/approach A zirconia slurry was inkjet-printed into a single layer of 316 SS powder and dried. Single bead experiments were conducted on the composite powder. The line type (continuous vs balling) and the melt pool geometry were compared at various levels of zirconia doping. Findings The balling regime expands dramatically with the zirconia dopant to both higher and lower energy density values indicating the presence of multiple physical mechanisms that influence the resulting melt track morphology. However, the energy density required for continuous tracks was not impacted as significantly by zirconia addition. These results suggest that the addition of dopants may alter the process parameter ranges suitable for the fabrication of high-quality parts. Originality/value This work provides new insight into the potential impact of material doping on the ranges of energy density values that form continuous lines in single bead tests. It also illustrates a potential method for spatially varying material composition for process development or even part optimization in powder bed fusion without producing a mixed powder that cannot be recycled.

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Laser Powder Bed Fusion Additive Manufacturing of Oxide Dispersion Strengthened Steel Using Gas Atomized Reaction Synthesis Powder

Cited by 2 publications

References 48 publications

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Impact of zirconia slurry in steel powder on melt pool characteristics in laser powder bed fusion

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