In-situ synthesis of oxides by reactive process atmospheres during L-PBF of stainless steel

Haines, Michael; Peter, Nicolas J.; Babu, S. S.; Jägle, Eric Aimé

doi:10.1016/j.addma.2020.101178

Cited by 31 publications

(22 citation statements)

References 45 publications

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“…Overall, this appears to be acceptable for the robust grade 316L stainless steel, and the reported oxygen and nitrogen differences can be considered small. In comparison to recently published work, [23] the measured oxygen seems to be higher and this result is connected to the higher oxygen content from the feedstock powder used herein. Both work highlight a significant oxygen loss from the powder to the built material.…”

Section: Resultscontrasting

confidence: 67%

Effect of the Process Gas and Scan Speed on the Properties and Productivity of Thin 316L Structures Produced by Laser-Powder Bed Fusion

Pauzon

Leicht

Klement

et al. 2020

Metall Mater Trans A

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The development of the laser powder bed fusion (L-PBF) process to increase its robustness and productivity is challenged by ambitious design optimizations, such as thin wall structures. In this study, in addition to the effect of commonly used gases as Ar and N2, increased laser scanning speed and new process gases, such as helium, were successfully implemented. This implementation allowed to build 316L stainless steel components with thin walls of 1 mm thickness with an enhanced build rate of 37 pct. The sample size effect and the surface roughness were held responsible for the reduction in strength (YS > 430 MPa) and elongation (EAB > 30 pct) for the 1 mm samples studied. Similar strength was achieved for all process gases. The increased scanning speed was accompanied by a more random texture, smaller cell size, and grain size factor along the building direction when compared to the material built with the standard laser parameters. Stronger preferential orientation 〈101〉 along the building direction was observed for material built with standard parameters. Finally, the use of helium as a process gas was successful and resulted in reduced cell size. This finding is promising for the future development of high strength 316L stainless steel built with high build rates.

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Section: Resultscontrasting

confidence: 67%

Effect of the Process Gas and Scan Speed on the Properties and Productivity of Thin 316L Structures Produced by Laser-Powder Bed Fusion

Pauzon

Leicht

Klement

et al. 2020

Metall Mater Trans A

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“…20,[74][75][76][77][78][79] Atom probe and electron microscopy studies have identified these inclusions as primarily oxides in austenitic SLM and DED SS without evidence of discrete MnSrich inclusions in as-built components. 2,20,80 These oxides are prevalent in AM microstructures in part due to the typically elevated oxygen content of as-built material originating from the feedstock and build chamber atmosphere (see Powder Feedstock, section 4). 20,80 The impact of these differences on the relative corrosion behavior will now be discussed with focus on austenitic SS where research to date has been centered.…”

Section: Nonmetallic Inclusionsmentioning

confidence: 99%

“…2,20,80 These oxides are prevalent in AM microstructures in part due to the typically elevated oxygen content of as-built material originating from the feedstock and build chamber atmosphere (see Powder Feedstock, section 4). 20,80 The impact of these differences on the relative corrosion behavior will now be discussed with focus on austenitic SS where research to date has been centered.…”

Section: Nonmetallic Inclusionsmentioning

confidence: 99%

Corrosion of Additively Manufactured Stainless Steels—Process, Structure, Performance: A Review

Schindelholz

Rodelas

2021

Corrosion

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The corrosion of additively manufactured (AM) metallic materials, such as stainless steels (SS), is a critical factor for their qualification and reliable use. This review assesses the emerging knowledgebase of powder-based laser AM SS corrosion and environmentally assisted cracking (EAC). The origins of AM-unique material features and their hierarchal impact on corrosion and EAC are addressed relative to conventionally processed SS. The effects of starting material, heat treatment and surface finishing are substantively discussed. An assessment of the current status of AM corrosion research, scientific gaps and research needs with greatest impact for AM SS advancement and qualification is provided.

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“…There are no commercial tools that can automate with registration to CAD geometries. Furthermore, the above data needs to be coupled with equipment data sets which logs the chemical species (O 2 concentrations), similar to Korinko et al [49] and Haines et al [50] ) and surface displacement (e.g., topology measurement done by Baucher et al [14] ) within the processing environment to usher in voxelby-voxel description of thermo-mechanical-chemical signatures.…”

Section: Future Directions For Deployment Of Ir Monitoring Methodomentioning

confidence: 99%

In-Situ Monitoring for Defect Identification in Nickel Alloy Complex Geometries Fabricated by L-PBF Additive Manufacturing

McNeil

Sisco

Frederick

et al. 2020

Metall Mater Trans A

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Published literature shows defect formation during laser powder bed fusion additive manufacturing (AM) of nickel base superalloys are sensitive to alloy chemistry, processing conditions, and geometry. In this work, ability to detect spatial distributions of defects is explored using in-situ monitoring of thermal signatures and surfaces. Simple and complex geometrical components were fabricated with CM247-LCÒ powder in an AM machine outfitted with optical and thermal sensors. The spatial and temporal variations of thermal signatures (peak intensity, decay, and number of gyrations), as well as, layer-by-layer optical images were analyzed. The observed thermal signatures were also verified with an analytical model for layer-wise heat transfer simulation that is sensitive to laser raster scan strategies. The cross-comparison data with reference to defects, obtained by X-ray tomography, were correlated with in-situ observations.

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In-situ synthesis of oxides by reactive process atmospheres during L-PBF of stainless steel

Cited by 31 publications

References 45 publications

Effect of the Process Gas and Scan Speed on the Properties and Productivity of Thin 316L Structures Produced by Laser-Powder Bed Fusion

Effect of the Process Gas and Scan Speed on the Properties and Productivity of Thin 316L Structures Produced by Laser-Powder Bed Fusion

Corrosion of Additively Manufactured Stainless Steels—Process, Structure, Performance: A Review

In-Situ Monitoring for Defect Identification in Nickel Alloy Complex Geometries Fabricated by L-PBF Additive Manufacturing

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