Microstructure and Oxidation Behavior Comparison Between Vertical, Upskin and Unsupported Downskin of SS316L LPBF Dome Structure
Bibliographic record
Abstract
As the laser powder bed fusion (LPBF) technology progresses, developing protocols for reducing and/or supportless printing of overhang downward-facing surfaces becomes increasingly critical for enhancing the economic and environmental efficiency of the process.The present study investigates the possible mismatch in microstructural, mechanical and oxidation behaviour of LPBF SS316L samples printed at 90 and 0 angles and including downward-facing low-angle overhang surfaces, in both as-built and heat-treated conditions.In as-built (AB) condition, primary dendrite arm spacing (PDAS) was measured at 0.72 0.09 and 3.19 0.20 m for the bulk and downskin surface, yielding a microhardness value of 244 5 and 225 3 HV, respectively.In addition, secondary dendritic arms are observed to form at the downskin, where the secondary dendrite arm spacing (SDAS) is measured at 0.99 0.18 m.A continuous growth model microsegregation analysis showed microsegregation level near equilibrium values.For the heat treated (HT) condition, the cellular structure recrystallized, leading to a grain size measurement of 31 3 and 26 3 m at the bulk and downskin surfaces, respectively, revealing that the grain growth rate observed at the downskin surfaces is slower than that of the bulk.The microhardness values were measured at 184 4 and 195 3 HV for the HT bulk and downskin surfaces.Post 100 hrs. of oxidation treatment at 900C, x-ray diffraction (XRD) analysis confirmed the formation of Fe2O3, Cr2O3, Cr2FeO4 and Cr2MnO4 oxides at the AB and HT bulk and downskin surfaces.While the scale thickness for the bulk and downskin were measured at 3.7 1.7, 3.8 1.8 and 7.9 2.4 and 7.1 2.1 m for the AB and HT condition, respectively.Electron dispersive spectroscopy (EDS) analysis revealed the formation of SiO2 oxide along the grain boundaries. III RsumAu fur et mesure que la technologie LPBF progresse, le dveloppement de protocoles pour l'impression rduite et/ou sans support de surfaces en porte--faux orientes vers le bas devient de plus en plus essentiel pour amliorer l'efficacit conomique et environnementale du processus.Par consquent, cette thse pose un contexte fondamental de la procdure, des paramtres, des proprits rsultantes et de sa performance conomique globale.Avec un manque de connaissances dans la littrature disponible, cette recherche cherche apporter de nouvelles ides et de nouveaux rsultats pour dvelopper et explorer davantage ladite technologie.La prsente tude examine le dcalage possible dans le comportement microstructurel, mcanique et l'oxydation des chantillons LPBF SS316L imprims des angles de 90 et 0 et y compris les surfaces en porte--faux faible angle orientes vers le bas, la fois dans des conditions telles que construites et traites thermiquement.Dans des conditions AB, le PDAS a t mesur 0,72 0,09 et 3,19 0,20 m pour la surface en vrac et la surface duvet, ce qui a donn une valeur de microduret de 244 5 et 225 3 HV, respectivement.De plus, on observe la formation de bras dendritiques secondaires au niveau de la peau duveteuse, o le SDAS est mesur 0,99 0,18 m.Une analyse de microsgrgation sur modle de croissance continue a montr un niveau de microsgrgation proche des valeurs d'quilibre.Pour la condition HT, on observe que la structure cellulaire se recristallise, ce qui conduit une mesure de la taille des grains de 31 3 et de 26 3 m aux surfaces de la peau en vrac et de la peau duveteuse, respectivement, rvlant que le taux de recristallisation observ aux surfaces de la peau infrieure est plus lent que celui de la peau en vrac.Les valeurs de microduret ont t mesures 184 4 et 195 3 HV sur les surfaces HT en vrac et en duvet.Poste 100 hrs.traitement oxydatif 900C, l'analyse XRD a confirm la IV formation d'oxydes Fe2O3, Cr2O3, Cr2FeO4 et Cr2MnO4 sur les surfaces en vrac et en duvet AB et HT.Alors que l'paisseur de l'chelle pour le vrac et le duvet est mesure 3,7 1,7, 3,8 1,8 et 7,9 2,4 et 7,1 2,1 m pour les conditions AB et HT, respectivement.L'analyse EDS a rvl la formation d'oxyde de SiO2 le long des joints de grains.Ces informations permettent de poursuivre les dveloppements vers une commercialisation russie de la fabrication sans support LPBF.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".