Material Composition and Sintering Behavior of PLA Bound Ni718 in Ambient Conditions

Material Composition and Sintering Behavior of PLA Bound Ni718 in Ambient Conditions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Material Composition and Sintering Behavior of PLA Bound Ni718 in Ambient Conditions Scott Downard, Brian Wisner This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7246505/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Nov, 2025 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted 5 You are reading this latest preprint version Abstract Fused filament fabrication (FFF) has become an increasingly popular method for private consumers given its low capital cost. With the development of metal-polymer feedstock material, which can theoretically provide anyone with access to metal components with complex geometry at no machining costs, it is an attractive option. This is especially true for metal alloys that are difficult to produce and used in high end applications such as Ni718. However, the nature of a simple FFF manufacturing process may inhibit the benefits of using such material and must be taken into consideration. This work provides clear expectations of an exceptionally low-cost FFF method to produce Ni718 using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive X-ray Spectroscopy (EDS) to visually evaluate the sintering quantity of the produced material and quantify the final material’s chemical composition. Results show that the final composition contains nearly 30% unwanted content by weight with little particle necking or sintering taking place limiting the use cases for such a material system. Additive Manufacturing Ni718 Fused Filament Fabrication Metal Injection Molding Scanning Electron Microscopy Energy Dispersive X-ray Spectroscopy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Glossary Fused Filament Fabrication – 3D printing process utilizing a metal/polymer feedstock to extrude layered material which requires later polymer removal Scanning Electron Microscopy – Micro-scale material investigation with a focused electron beam to scan over a surface Energy Dispersive X-ray Spectroscopy – Element identification using emitted characteristic x-rays following electron bombardment Necking – Metal particle deformation during sintering 1. Introduction Fused Filament Fabrication (FFF), a process similar to Metal Injection Molding (MIM), has been a staple in the Additive Manufacturing (AM) industry since the late 1980s when Stratasys invented Fused Deposition Modeling (FDM) [ 1 ]. While a significant portion of this activity since then has been limited to polymer filaments, an increasing number of metal powder/polymer feedstocks have been produced. Stainless steels, titanium, and cobalt alloys have been of interest to the medical industry for their biocompatibility [ 2 ]. FFF is typically associated with prototyping a low capital cost and a relatively high degree of sustainability [ 3 ], making its applicability towards producing metal components a highly marketable option that can be aimed at private consumers. Though these metal materials produced with FFF generally exhibit reduced mechanical properties in comparison to wrought materials and other AM methods [ 4 – 6 ]. Drastically reduced strength could be concerning for consumers who may not be as well versed in the AM complications that are attempting to use FFF produced metals which are traditionally used in high strength applications. There are three primary steps to the metal FFF process which can impact resulting material properties including the filament compounding, printing, and the post-processing of the printed component. Filament compounding is conducted prior to being sold to private consumers which helps reduce, but not eliminate [ 7 ], safety issues of directly handling metal powders that would otherwise be present to a higher degree [ 8 , 9 ]. Metal powder selection is made based on the desired final component material and will dictate the sintering temperature required, while the binding material can be highly variable and has a significant impact on the required post-processing steps [ 10 , 11 ]. Print settings can vary both by printer and composition of the filament used, with changes in print parameters causing differences in porosity and strength in the as-printed (green) as well as the final part [ 12 – 14 ]. Post-processing of the printed parts is directly dependent on which metal powder is used and the need to remove the binding material (debinding) prior to sintering. Binders can be made of one or multiple materials, with benefit of a multi-component binder being the ability to implement a chemical solvent or two-part thermal debind which can provide gas permeable pathways for the primary polymer to vaporize during thermal debinding [ 6 , 11 , 15 , 16 ]. An increase in sintering temperature has also been shown to aid in the decarbonization of 420 stainless steel produced by MIM [ 17 ]. In this work, a commercially available filament made from Ni718 powder bound with Polylactic acid (PLA) will be thermally debound and sintered in an ambient atmosphere. Samples will be processed as the filament manufacturer specifies, and the resulting part composition will be determined using Energy Dispersive X-ray Spectroscopy (EDS) on a Scanning Electron Microscope (SEM). Similar EDS work has been conducted on the same filament manufactures bronze-PLA filament [ 18 ], and to a limited extent with Ni718 [ 19 ], but the high oxygen content observed was not decoupled from potential additions from the atmosphere. In addition to the alloying elements present in Ni718, oxygen and Carbon content within the final part will be of specific interest, as previously mentioned residual binder materials can hinder the sintering quality of the metal powder, in addition to oxidization of Ni718 at elevated temperatures [ 20 , 21 ]. However, it should be noted that light elements, such as oxygen and carbon, are generally difficult to capture accurately with EDS [ 22 ]. However, the EDS detector utilized for this study is optimized for distinguishing these low energy peaks, therefore a direct analysis of results will be presented. The resulting samples produced with metal FFF are also subject to potential inconsistencies in metal/polymer ratio during the compounding, though a generally consistent level of contaminants is expected to be presented. 2. Materials & Methods 2.1 Sample Printing Samples were printed using a Creality Ender 3 Pro equipped with a Creality Original Ender 3 Direct Drive Upgrade Kit and a 0.6 mm hardened steel nozzle. The Ni718/PLA filament used was acquired from Virtual Foundry (Stoughton, Wisconsin, USA) which contains greater than 80% Ni718 powder by weight, with the remaining percentage consisting of primarily PLA and a small but unknown quantity of their proprietary binding additive. Printing was done without the Virtual Foundry recommended filawarmer. UltiMaker Cura was used as the slicing software for the test samples, of which there were a total of six samples produced with dimensions of 5x40x5 mm. The remaining printer settings are shown in Table 1 . Table 1 Ender 3 Printer Settings Print Speed (mm/s) 60 Layer Height 0.2 Wall Layers 1 Top/Bottom Layers 0 Nozzle Temperature (°C) 230 Bed Temperature (°C) 60 Infill (%) 100 Infill Pattern Zig-Zag Infill Overlap (%) 50 Flow (%) 132.5 2.2 Sample Post-Processing All samples followed the Virtual Foundry specified furnace schedules in ambient atmosphere (17–25°C and 50–90% humidity) using a Lindberg/Blue 51894 box furnace for debinding and a Thermolyne Type 46100 for sintering. Temperatures reached during debinding and sintering were 427°C and 1232°C, respectively, with both processes allowed to cool naturally to room temperature while remaining in the furnace. Full furnace programs used can be seen in Table 2 . Of the original six printed samples, three were produced as control and the remaining three were intentionally allowed to be “contaminated” with additional exposure to ambient atmosphere by reducing the quantity of shielding ballast. Table 2 Thermal Debinding and Sintering Furnace Schedules Debinding Sintering Segment Duration (hr) Segment Duration (hr) 20°C → 204°C 2 20°C → 593°C 0.5 204°C Hold 2 593°C Hold 2 204°C → 427°C 2 593°C → 1232°C 2 427°C Hold 2 1232°C Hold 4 Natural Cooling Natural Cooling Both conditions were packed in 300 mL alumina crucibles with steel blend and sintering carbon, all three of which were also acquired from Virtual Foundry. For debinding, all samples were centered lengthwise vertically in the crucibles which were filled with 450 g of steel blend that occupied all but the top 10 mm of the crucible. Prior to sintering, the control samples were given an additional 40 g layer of sintering carbon which filled the remainder of the crucible. The contaminated samples only received a 7 g layer of sintering carbon which delayed the onset of oxidization to the ballast and sample, allowing for only a portion of both to oxidize during the sintering process. Control samples were also processed with alumina lids on top of the crucible which were split down the middle and placed with a 10 mm gap in order to reduce the rate of air flow into the crucible, as it is a recommendation of Virtual Foundry to not fully restrict air flow to allow for the vaporized PLA to escape. Samples were stored in a vacuum desiccator at no greater than − 0.07 MPa once thermally processed outside of polishing or transportation to the SEM. After completion of thermal processing, each sample was polished on all long sides with a Pace Technologies Nano 1000T polisher operating at 200 RPM with four progressively finer SiC discs. The duration and grit of each polishing step performed on all sides of the sample are shown in Table 3 , with the sample rotated 180° halfway through each duration to prevent excessive scoring marks. This polishing procedure was found though prior testing of additional samples to retain maximum thickness while removing all ballast material from the surface. Immediately prior to SEM use, any scanned side of a sample was additionally polished for 30 seconds with a 1200 grit disc to remove any potential oxide layer that accumulated during storage. After polishing, all scanned surfaces were cleaned with isopropyl alcohol and dried. Table 3 Sample SiC Polishing Schedule SiC Grit Duration (sec) 180 70 360 30 600 30 1200 120 Once surface line scans were completed, each of the six samples were cut on a LECO VC-50 saw with a 0.4 mm wide blade into six approximately equal length portions. All sections were also EDS line scanned on the top side parallel and tangential to the layer lines through the center of the section. This was done to address whether vaporized PLA was attempting to permeate preferential to its layer line direction. 2.3 Scanning Electron Microscope & EDS Both EDS line scans and maps were collected in this work using a Tescan Vega II SEM equipped with an Oltim® Max 65 EDS detector running the AZtecLive software. This EDS detector has a resolution at CK of 46 eV or better at all count rates up to 50,000 cps, this resolution is better for distinguishing light elements. All line scans for this study were recorded with an accelerative voltage of 30 kV, working distances of 11.5–12 mm, and 100x magnification. At this magnification each sample required a series of 19 line scans to reach the full length of each sample, with two or three windows being necessary for one internal line scan. Each line scan window was recorded as a five-line array, spanning approximately 0.75 mm. All line arrays were averaged together by element every 4.4 µm then stitched together and smoothed with a fifth order Savitzky-Golay filter to create the full-length line. Seven EDS maps were also measured at equal increments along the length of a sample at 100x and 500x to be compared to the full-length line scan to determine if the line scan arrays were sufficiently capturing bulk material composition. Internal cross-section line scans were performed after cutting the samples into six segments. Section line scans were collected with identical SEM parameters and measured through each section’s center in two directions, parallel and perpendicular to the original layer lines. The layout of all EDS scans can be seen visually in Fig. 1 , all cross-section cuts have been given a letter designation for future reference. 3. Results & Discussion 3.1 Produced Samples Examples of both sample conditions can be seen in Fig. 2 , with a clearly oxidized region on the left side of the contaminated sample, however both have visible pores throughout their full lengths. Each sample can also be seen to have discoloration around its edges where polishing did not remove portions of the sintering ballast which adhered to the samples during sintering. Artifacts from these areas will be visible in later EDS scans and will be disregarded for final composition results. Edge defects being so prevalent in these samples exemplifies the need for FFF components to be printed oversized as the exterior surfaces will need significant cleaning following the post processing phases. Differences between conditions are also apparent on the internal cross sections of each sample, some of which are shown in Fig. 3 . Images were recorded at an average of 6.0 mm from the contaminated end (and equivalent end of control samples), and 7.0 mm from the opposite end (noncontaminated) of each sample. Image cross section labels are in reference to those shown in Fig. 1 . It can be seen from these cross sections that, regardless of condition or location, little necking of metal powder particles occur given that borders between particles are clearly discernible throughout the sample. This is especially true for regions of porosity, which based on presences of carbon content spikes shown later are results of trapped PLA, have contaminants preventing sintering between powder particles. It has been shown by Jiang et al. that this material can experience improved sintering with reduced porosity be utilizing higher temperatures during sintering [ 19 ]. Internal porosity appeared to be highly directional in line with the printing layer orientation. 3.2 Length Scan Results Given the resolutions of the full-length line scans, large variations in data are present from data points collected on metal powder particles, between particles, on pores, etc. An example of the original collected data overlayed by its Savitsky-Golay smoothed line is shown in Fig. 4 , only smoothed lines will be presented in the remaining figures. Comparing the set of seven recorded surface EDS maps plotted in a series alongside its equivalent line scan in Fig. 5 , we see both scanning methods are nearly identical, even when looking at a light element. Regions of intentional contamination were clearly present within the EDS full length scans. Figure 6 compares the oxygen content of all six samples by their condition, where the oxygen is exceptionally high in the first portions of the contaminated samples while the control samples are consistent over their length. However, the contaminated samples converge to the same oxygen content as the control samples. Along with this increase in oxygen content, the majority of metallic element content reduced when given as a weight percent given the large increase in oxygen. However, iron saw a significant increase coupled with oxygen. Profiles of the three primary alloying elements are shown in Fig. 7 along with carbon, which is present in a substantial quantity at greater than 10 wt% over the length of all samples. One explanation for the increase in iron wt% seen in areas exposed to excessive oxygen is provided by Xu et al. [ 21 ], where Ni-based alloys containing high iron and low aluminum contents exhibit high mass gain from iron-rich oxide scale formation, even in an alloy containing far greater chromium content than was present in our study’s material. As previously mentioned, the excessive amount of carbon present within this material could be a result of residual material from PLA degradation, or an inability for the degraded PLA to escape from within the present metal powder. Multiple lines visible in Fig. 7 exhibit sample edge effects mentioned previously regarding Fig. 2 . 3.3 Cross Section Scan Results Significant porosity, visible in Fig. 3 , was present within all contaminated and control specimens, resulting in a high quantity of content variation on the cross-section surfaces. Cross section line scans can again be seen to have the edge contents of the samples that are from sintering ballast residue. Figures 8 and 9 show element content profiles across the centers of cross sections B and F, respectively. Oxygen content remains the primary difference between contaminated and control samples within these scans with two distinct levels of content present within Fig. 8 a, which as before is coupled with an increase in iron content. In comparison to the cross sections at the opposite end of the samples in Fig. 9 , the content of the two samples conditions has equalized. Looking closely at the oxygen content of both cross sections, there seems to be a slight increase in content towards the center of the specimens while carbon content remains at a similar level through the thickness. However, comparing the carbon content of the two cross sections with the full-length line scans, there is a higher concentration of carbon within the specimens as compared to on the surface, especially in regard to the control samples. This reduction in oxygen towards the exterior of the sample with the constant level of carbon would lend itself to the conclusion that vaporized PLA is escaping the material more efficiently at the outside of the samples, but a carbon residual is left behind from the degradation itself regardless of depth. 3.4 Resulting Composition Comparison With the filament manufacturers provided SDS for the Ni718/PLA filament, a final composition of fully debound material can be estimated. Values for each element were found assuming no residual material from PLA remained after sintering, and by taking equal ratios of each materials initial content ranges provided. These values are compared to this study’s EDS findings in Table 4 . Comparison values from this work were determined by extracting the central 90% of each line scanned from internal cross sections of control samples. The mean weight percents from all internal values were found and scaled proportionally to sum to 100%. Table 4 Estimated Content Comparison to EDS Results Element Filament SDS EDS Result Nickel 55.76 32.24 Chromium 16.67 17.75 Iron 16.67 12.07 Niobium 4.20 4.13 Molybdenum 4.20 2.74 Titanium 0.84 1.07 Aluminum 0.84 1.08 Carbon 0.84 18.99 Oxygen - 9.91 Results of the study are clear regarding the excessive quantity of the final material composition of carbon and oxygen reaching almost 30% of the final material weight. This undesirable composition coupled with the clear porosity and lack of sintering shown back in Fig. 3 , one would expect an exceptionally low strength material, which is generally not an expectation of a Ni-based alloy. 4. Conclusion This study establishes clear expectations for FFF Ni718 bound with PLA when thermally processed in ambient conditions. While the FFF method can produce custom geometries, it does have limitations resulting from the post processing requirements. Thermal processing of metals at high temperatures provides the challenge of dealing with oxidation, an issue which can be amplified by introducing a polymer throughout the material which will need to vaporize. This work showed that shielding materials during sintering can reduce the oxidation of Ni718 during ambient thermal processes, but the resulting material still contains almost 30% of unwanted carbon and oxygen. Manufacturing with metal FFF also necessitates the oversizing of parts before printing to account for shrinkage as a result of sintering and surface cleaning, as surface contaminants of this study are clearly present even after moderate surface polishing. Samples produced in this study also exhibited little powder particle necking, while it is uncertain if this is a result of the contamination or sintering and debinding schedules. Utilizing inert atmospheres during thermal debinding could be a beneficial process improvement for this material [ 23 ], however, it is evident that portions of the contaminating elements are present regardless of excessive oxygen and are instead caused by the PLA degradation. Though these potential improvements are contradictory towards an affordable metal FFF method. Previously mentioned work conducted by Xu et al. [ 21 ] found that using a Ni-based alloy with lower iron and higher aluminum content saw a significant reduction in mass gain from oxidization at elevated temperatures. Given the present processing parameters suggested for this study’s Ni718, it would be difficult for this material to fulfil its high-strength applications, though this would still need verification though mechanical testing. Iron is also used in Ni718 to improve workability [ 21 ], which would not be as necessary for an AM application. Utilizing a different Ni-based alloy could greatly improve the viability of this affordable AM method to produce components for critical applications. Declarations Competing Interests: The authors have no competing interests to declare that are relevant to the content of this article. Funding: No funding was received to assist with the preparation of this manuscript. Acknowledgements: The authors would like to thank Ohio University’s Physics & Astronomy Department for the use of their Scanning Electron Microscope. References Gibson, I., Rosen, D., Stucker, B., and Khorasani, M., 2021, Additive Manufacturing Technologies , Springer International Publishing, Cham. https://doi.org/10.1007/978-3-030-56127-7. Hamidi, M. F. F. A., Harun, W. S. W., Samykano, M., Ghani, S. A. C., Ghazalli, Z., Ahmad, F., and Sulong, A. B., 2017, “A Review of Biocompatible Metal Injection Moulding Process Parameters for Biomedical Applications,” Materials Science and Engineering: C, 78 , pp. 1263–1276. https://doi.org/10.1016/j.msec.2017.05.016. Ramazani, H., and Kami, A., 2022, “Metal FDM, a New Extrusion-Based Additive Manufacturing Technology for Manufacturing of Metallic Parts: A Review,” Prog Addit Manuf, 7 (4), pp. 609–626. https://doi.org/10.1007/s40964-021-00250-x. Downard, S., Clark, E., O’Brien, C., Mohammadlou, B. S., Kontsos, A., Celli, D., Smith, L., Al Amiri, E., Weems, A., and Wisner, B., 2024, “Influence of a Suboptimal Environment and Sintering Temperature on the Mechanical Properties of Fused Filament Fabricated Copper,” Int J Adv Manuf Technol, 135 (7–8), pp. 3129–3146. https://doi.org/10.1007/s00170-024-14697-z. Gong, H., Snelling, D., Kardel, K., and Carrano, A., 2019, “Comparison of Stainless Steel 316L Parts Made by FDM- and SLM-Based Additive Manufacturing Processes,” JOM, 71 (3), pp. 880–885. https://doi.org/10.1007/s11837-018-3207-3. Thompson, Y., Gonzalez-Gutierrez, J., Kukla, C., and Felfer, P., 2019, “Fused Filament Fabrication, Debinding and Sintering as a Low Cost Additive Manufacturing Method of 316L Stainless Steel,” Additive Manufacturing, 30 , p. 100861. https://doi.org/10.1016/j.addma.2019.100861. Tedla, G., Jarabek, A. M., Byrley, P., Boyes, W., and Rogers, K., 2022, “Human Exposure to Metals in Consumer-Focused Fused Filament Fabrication (FFF)/ 3D Printing Processes,” Science of The Total Environment, 814 , p. 152622. https://doi.org/10.1016/j.scitotenv.2021.152622. Arrizubieta, J. I., Ukar, O., Ostolaza, M., and Mugica, A., 2020, “Study of the Environmental Implications of Using Metal Powder in Additive Manufacturing and Its Handling,” Metals, 10 (2), p. 261. https://doi.org/10.3390/met10020261. Jacobson, M., Cooper, A. R., and Nagy, J., 1964, “Explosibility of Metal Powders,” United States Department of the Interior, Bureau of Mines Jacob, J., Pejak Simunec, D., Kandjani, A. E. Z., Trinchi, A., and Sola, A., 2024, “A Review of Fused Filament Fabrication of Metal Parts (Metal FFF): Current Developments and Future Challenges,” Technologies, 12 (12), p. 267. https://doi.org/10.3390/technologies12120267. Lotfizarei, Z., Mostafapour, A., Barari, A., Jalili, A., and Patterson, A. E., 2023, “Overview of Debinding Methods for Parts Manufactured Using Powder Material Extrusion,” Additive Manufacturing, 61 , p. 103335. https://doi.org/10.1016/j.addma.2022.103335. Kurose, T., Abe, Y., Santos, M. V. A., Kanaya, Y., Ishigami, A., Tanaka, S., and Ito, H., 2020, “Influence of the Layer Directions on the Properties of 316L Stainless Steel Parts Fabricated through Fused Deposition of Metals,” Materials, 13 (11), p. 2493. https://doi.org/10.3390/ma13112493. Moritzer, E., and Elsner, C. L., 2022, “Investigation and Improvement of Processing Parameters of a Copper-Filled Polymer Filament in Fused Filament Fabrication as a Basis for the Fabrication of Low-Porosity Metal Parts,” Macromolecular Symposia, 404 (1), p. 2100390. https://doi.org/10.1002/masy.202100390. Mathesius, M. B., Kozak, E., Scott-Emuakpor, O., and Siddiqui, S. F., 2025, “Investigating the Viability of Material Extrusion Additive Manufacturing of Inconel 718 for Fatigue Driven Applications,” AIAA SCITECH 2025 Forum , American Institute of Aeronautics and Astronautics, Orlando, FL. https://doi.org/10.2514/6.2025-1365. Thompson, Y., Zissel, K., Förner, A., Gonzalez-Gutierrez, J., Kukla, C., Neumeier, S., and Felfer, P., 2022, “Metal Fused Filament Fabrication of the Nickel-Base Superalloy IN 718,” J Mater Sci, 57 (21), pp. 9541–9555. https://doi.org/10.1007/s10853-022-06937-y. Gonzalez-Gutierrez, J., Godec, D., Kukla, C., Schlauf, T., Burkhardt, C., and Holzer, C., 2017, SHAPING, DEBINDING AND SINTERING OF STEEL COMPONENTS VIA FUSED FILAMENT FABRICATION . Lou, J., Liu, M., He, H., Wang, X., Li, Y., Ouyang, X., and An, C., 2020, “Investigation of Decarburization Behaviour during the Sintering of Metal Injection Moulded 420 Stainless Steel,” Metals, 10 (2), p. 211. https://doi.org/10.3390/met10020211. Lu, Z., Ayeni, O. I., Yang, X., Park, H.-Y., Jung, Y.-G., and Zhang, J., 2020, “Microstructure and Phase Analysis of 3D-Printed Components Using Bronze Metal Filament,” J. of Materi Eng and Perform, 29 (3), pp. 1650–1656. https://doi.org/10.1007/s11665-020-04697-x. Jiang, C.-P., Masrurotin, M., Ramezani, M., Wibisono, A. T., Toyserkani, E., and Macek, W., 2024, “Sintering Parameter Investigation for Bimetallic Stainless Steel 316L/Inconel 718 Composite Printed by Dual-Nozzle Fused Deposition Modeling,” RPJ, 30 (8), pp. 1624–1637. https://doi.org/10.1108/rpj-04-2024-0163. Greene, G. A., and Finfrock, C. C., 2001, “Oxidation of Inconel 718 in Air at High Temperatures,” Oxidation of Metals, 55 (5), pp. 505–521. https://doi.org/10.1023/A:1010359815550. Xu, Y., Gu, Y., Yan, J., and Sun, F., 2017, “Oxidation Behavior of Ni-Based Alloys: Effect of Alloying Additions,” Corrosion, 73 (3), pp. 247–255. https://doi.org/10.5006/2192. “Is Scanning Electron Microscopy/Energy Dispersive X‐ray Spectrometry (SEM/EDS) Quantitative?” https://doi.org/10.1002/sca.21041. Raza, M., Ahmad, F., MUHAMAD, N., Bakar, A., Omar, mohd afian, Akhtar, M., Aslam, M., and SHERAZI, I., 2017, “Effects of Debinding and Sintering Atmosphere on Properties and Corrosion Resistance of Powder Injection Molded 316 L - Stainless Steel,” Sains Malaysiana, 46 , pp. 285–293. https://doi.org/10.17576/jsm-2017-4602-13. Supplementary Files Ni718ContVisualAbstractFinal.png Cite Share Download PDF Status: Published Journal Publication published 13 Nov, 2025 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted Editorial decision: Major Revisions Needed 28 Oct, 2025 Reviewers agreed at journal 06 Oct, 2025 Reviewers invited by journal 01 Aug, 2025 Editor assigned by journal 31 Jul, 2025 First submitted to journal 29 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7246505","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":494326314,"identity":"9c3f205f-66c8-40b9-8eff-3a5e3dbfd81b","order_by":0,"name":"Scott Downard","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Scott","middleName":"","lastName":"Downard","suffix":""},{"id":494326315,"identity":"bdfebd09-9a17-42a3-a01b-e16ced38a67d","order_by":1,"name":"Brian Wisner","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAt0lEQVRIiWNgGAWjYBACAwbGBhAtxyABZjATr8WYFC0QkNggAaaJ0GIukdz8uaDiXnq/dHPjA4YK68QGQlosZyS2Sc84U5w7c87BZgOGM+mEtRjcTmxj5m1LyN1wI7FNgrHtMFFamj/z/ktINwBr+UeclgZp3oaEBIiWBiK0WM5/2CbNcyzBcOaMxGaDhGPpxgS1mPMcf/yZpyZBnl8i/eGDDzXWsgS1oIIE0pSPglEwCkbBKMAFAAd7P2TJp2hhAAAAAElFTkSuQmCC","orcid":"","institution":"Ohio University Russ College of Engineering and Technology","correspondingAuthor":true,"prefix":"","firstName":"Brian","middleName":"","lastName":"Wisner","suffix":""}],"badges":[],"createdAt":"2025-07-29 20:15:39","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7246505/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7246505/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00170-025-16944-3","type":"published","date":"2025-11-13T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88948810,"identity":"21f6956d-e160-452c-9916-2bff56adc253","added_by":"auto","created_at":"2025-08-13 05:36:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":102569,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eLayout of EDS Scans Conducted on Each Sample\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure1EDSLayout.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/f02d71f7055f2a0651bfce86.png"},{"id":88950093,"identity":"9bdf2f8d-bc53-4807-9896-f5685ee29c7d","added_by":"auto","created_at":"2025-08-13 05:44:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":160595,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOptical Microscope Comparison at 50x Magnification: a) Contaminated Sample, b) Control Sample\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure2SampleExamples.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/1103a85975794af1f773b55a.png"},{"id":88948822,"identity":"66a4f4d7-0c39-42eb-8c28-35f9452ba5eb","added_by":"auto","created_at":"2025-08-13 05:36:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":388226,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eInternal Cross Section SEM Images at 100x: a) Contaminated Sample, Cross Section B; b) Contaminated Sample, Cross Section F; c) Control Sample, Equivalent Cross Section B; d) Control Sample, Cross Section F\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure3SEMCrossSections.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/b31c47f0f5d3f902f82085f3.png"},{"id":88950094,"identity":"bf67a47e-f667-4090-a8c9-6663c4a0cad8","added_by":"auto","created_at":"2025-08-13 05:44:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":45093,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOriginal EDS data overlayed with post-processed smoothing\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure4RawVsSmoothedDataComparison.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/c85decf104a160c0dee8e7d0.png"},{"id":88948811,"identity":"cfd486f7-80aa-4510-8d00-d84bfbac60f3","added_by":"auto","created_at":"2025-08-13 05:36:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":39379,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eEDS Stitched Line Scan Compared to Incremental EDS Map Scans with Oxygen\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure5LineScanVsMapScans.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/f381aeb6fa0f5e1e2d564502.png"},{"id":88948814,"identity":"e38fcf81-6a1b-4140-8785-907f5814146e","added_by":"auto","created_at":"2025-08-13 05:36:24","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":46593,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eOxygen weight percent contributions by sample condition\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure6FullLengthEDSOxygenContent.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/470169da6e708c16b6334b70.png"},{"id":88951181,"identity":"e1b69147-545e-4cd7-bc4a-3361dfae7215","added_by":"auto","created_at":"2025-08-13 05:52:24","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":114736,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eAdditional element weight percent contributions by condition: a) Nickel, b) Carbon, c) Iron, d) Chromium\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure7FullLengthPrimaryElementWeightPercents.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/3a0979e76ada6f857eb9df49.png"},{"id":88948819,"identity":"7b35d4b3-6782-4bbc-a4cd-cd888b376d39","added_by":"auto","created_at":"2025-08-13 05:36:24","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":86318,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eCross Section B Depth EDS Line Scan Wt%: a) Oxygen, b) Carbon, c) Nickel, d) Iron\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure8CrossSectionBLineScans.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/05916bcb0acdec487faa7b53.png"},{"id":88948824,"identity":"2126fa8b-956e-4033-8f1e-b5413062f500","added_by":"auto","created_at":"2025-08-13 05:36:25","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":75676,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eCross Section F Depth EDS Line Scan Wt%: a) Oxygen, b) Carbon, c) Nickel, d) Iron\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Figure9CrossSectionFLineScans.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/5367f885f2f40dfab1389c3e.png"},{"id":96105032,"identity":"8d47b0cb-73da-41ca-89a1-514b394227af","added_by":"auto","created_at":"2025-11-17 16:07:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1549400,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/4f8c233a-3b9c-4137-acc8-f0ea62bb5ae1.pdf"},{"id":88948902,"identity":"0447646c-594c-4808-bcf4-f152243822b6","added_by":"auto","created_at":"2025-08-13 05:37:18","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"supplement","size":298532,"visible":true,"origin":"","legend":"","description":"","filename":"Ni718ContVisualAbstractFinal.png","url":"https://assets-eu.researchsquare.com/files/rs-7246505/v1/cc4a55fce30a5ecc1f56b3bc.png"}],"financialInterests":"","formattedTitle":"Material Composition and Sintering Behavior of PLA Bound Ni718 in Ambient Conditions","fulltext":[{"header":"Glossary","content":"\u003cp\u003eFused Filament Fabrication \u0026ndash; 3D printing process utilizing a metal/polymer feedstock to extrude layered material which requires later polymer removal\u003c/p\u003e\n\u003cp\u003eScanning Electron Microscopy \u0026ndash; Micro-scale material investigation with a focused electron beam to scan over a surface\u003c/p\u003e\n\u003cp\u003eEnergy Dispersive X-ray Spectroscopy \u0026ndash; Element identification using emitted characteristic x-rays following electron bombardment\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNecking \u0026ndash; Metal particle deformation during sintering\u003c/p\u003e"},{"header":"1. Introduction","content":"\u003cp\u003eFused Filament Fabrication (FFF), a process similar to Metal Injection Molding (MIM), has been a staple in the Additive Manufacturing (AM) industry since the late 1980s when Stratasys invented Fused Deposition Modeling (FDM) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. While a significant portion of this activity since then has been limited to polymer filaments, an increasing number of metal powder/polymer feedstocks have been produced. Stainless steels, titanium, and cobalt alloys have been of interest to the medical industry for their biocompatibility [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. FFF is typically associated with prototyping a low capital cost and a relatively high degree of sustainability [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], making its applicability towards producing metal components a highly marketable option that can be aimed at private consumers. Though these metal materials produced with FFF generally exhibit reduced mechanical properties in comparison to wrought materials and other AM methods [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Drastically reduced strength could be concerning for consumers who may not be as well versed in the AM complications that are attempting to use FFF produced metals which are traditionally used in high strength applications.\u003c/p\u003e\u003cp\u003eThere are three primary steps to the metal FFF process which can impact resulting material properties including the filament compounding, printing, and the post-processing of the printed component. Filament compounding is conducted prior to being sold to private consumers which helps reduce, but not eliminate [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], safety issues of directly handling metal powders that would otherwise be present to a higher degree [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Metal powder selection is made based on the desired final component material and will dictate the sintering temperature required, while the binding material can be highly variable and has a significant impact on the required post-processing steps [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Print settings can vary both by printer and composition of the filament used, with changes in print parameters causing differences in porosity and strength in the as-printed (green) as well as the final part [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Post-processing of the printed parts is directly dependent on which metal powder is used and the need to remove the binding material (debinding) prior to sintering. Binders can be made of one or multiple materials, with benefit of a multi-component binder being the ability to implement a chemical solvent or two-part thermal debind which can provide gas permeable pathways for the primary polymer to vaporize during thermal debinding [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. An increase in sintering temperature has also been shown to aid in the decarbonization of 420 stainless steel produced by MIM [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn this work, a commercially available filament made from Ni718 powder bound with Polylactic acid (PLA) will be thermally debound and sintered in an ambient atmosphere. Samples will be processed as the filament manufacturer specifies, and the resulting part composition will be determined using Energy Dispersive X-ray Spectroscopy (EDS) on a Scanning Electron Microscope (SEM). Similar EDS work has been conducted on the same filament manufactures bronze-PLA filament [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], and to a limited extent with Ni718 [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], but the high oxygen content observed was not decoupled from potential additions from the atmosphere. In addition to the alloying elements present in Ni718, oxygen and Carbon content within the final part will be of specific interest, as previously mentioned residual binder materials can hinder the sintering quality of the metal powder, in addition to oxidization of Ni718 at elevated temperatures [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. However, it should be noted that light elements, such as oxygen and carbon, are generally difficult to capture accurately with EDS [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. However, the EDS detector utilized for this study is optimized for distinguishing these low energy peaks, therefore a direct analysis of results will be presented. The resulting samples produced with metal FFF are also subject to potential inconsistencies in metal/polymer ratio during the compounding, though a generally consistent level of contaminants is expected to be presented.\u003c/p\u003e"},{"header":"2. Materials \u0026 Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Sample Printing\u003c/h2\u003e\u003cp\u003eSamples were printed using a Creality Ender 3 Pro equipped with a Creality Original Ender 3 Direct Drive Upgrade Kit and a 0.6 mm hardened steel nozzle. The Ni718/PLA filament used was acquired from Virtual Foundry (Stoughton, Wisconsin, USA) which contains greater than 80% Ni718 powder by weight, with the remaining percentage consisting of primarily PLA and a small but unknown quantity of their proprietary binding additive. Printing was done without the Virtual Foundry recommended filawarmer. UltiMaker Cura was used as the slicing software for the test samples, of which there were a total of six samples produced with dimensions of 5x40x5 mm. The remaining printer settings are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEnder 3 Printer Settings\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePrint Speed (mm/s)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLayer Height\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWall Layers\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTop/Bottom Layers\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNozzle Temperature (\u0026deg;C)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e230\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBed Temperature (\u0026deg;C)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInfill (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInfill Pattern\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eZig-Zag\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInfill Overlap (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFlow (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e132.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Sample Post-Processing\u003c/h2\u003e\u003cp\u003eAll samples followed the Virtual Foundry specified furnace schedules in ambient atmosphere (17\u0026ndash;25\u0026deg;C and 50\u0026ndash;90% humidity) using a Lindberg/Blue 51894 box furnace for debinding and a Thermolyne Type 46100 for sintering. Temperatures reached during debinding and sintering were 427\u0026deg;C and 1232\u0026deg;C, respectively, with both processes allowed to cool naturally to room temperature while remaining in the furnace. Full furnace programs used can be seen in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Of the original six printed samples, three were produced as control and the remaining three were intentionally allowed to be \u0026ldquo;contaminated\u0026rdquo; with additional exposure to ambient atmosphere by reducing the quantity of shielding ballast.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eThermal Debinding and Sintering Furnace Schedules\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eDebinding\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eSintering\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSegment\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDuration (hr)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSegment\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDuration (hr)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u0026deg;C \u0026rarr; 204\u0026deg;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e20\u0026deg;C \u0026rarr; 593\u0026deg;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e204\u0026deg;C Hold\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e593\u0026deg;C Hold\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e204\u0026deg;C \u0026rarr; 427\u0026deg;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e593\u0026deg;C \u0026rarr; 1232\u0026deg;C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e427\u0026deg;C Hold\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1232\u0026deg;C Hold\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eNatural Cooling\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eNatural Cooling\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eBoth conditions were packed in 300 mL alumina crucibles with steel blend and sintering carbon, all three of which were also acquired from Virtual Foundry. For debinding, all samples were centered lengthwise vertically in the crucibles which were filled with 450 g of steel blend that occupied all but the top 10 mm of the crucible. Prior to sintering, the control samples were given an additional 40 g layer of sintering carbon which filled the remainder of the crucible. The contaminated samples only received a 7 g layer of sintering carbon which delayed the onset of oxidization to the ballast and sample, allowing for only a portion of both to oxidize during the sintering process. Control samples were also processed with alumina lids on top of the crucible which were split down the middle and placed with a 10 mm gap in order to reduce the rate of air flow into the crucible, as it is a recommendation of Virtual Foundry to not fully restrict air flow to allow for the vaporized PLA to escape. Samples were stored in a vacuum desiccator at no greater than \u0026minus;\u0026thinsp;0.07 MPa once thermally processed outside of polishing or transportation to the SEM.\u003c/p\u003e\u003cp\u003eAfter completion of thermal processing, each sample was polished on all long sides with a Pace Technologies Nano 1000T polisher operating at 200 RPM with four progressively finer SiC discs. The duration and grit of each polishing step performed on all sides of the sample are shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, with the sample rotated 180\u0026deg; halfway through each duration to prevent excessive scoring marks. This polishing procedure was found though prior testing of additional samples to retain maximum thickness while removing all ballast material from the surface. Immediately prior to SEM use, any scanned side of a sample was additionally polished for 30 seconds with a 1200 grit disc to remove any potential oxide layer that accumulated during storage. After polishing, all scanned surfaces were cleaned with isopropyl alcohol and dried.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSample SiC Polishing Schedule\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSiC Grit\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDuration (sec)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e180\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e360\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e600\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1200\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e120\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eOnce surface line scans were completed, each of the six samples were cut on a LECO VC-50 saw with a 0.4 mm wide blade into six approximately equal length portions. All sections were also EDS line scanned on the top side parallel and tangential to the layer lines through the center of the section. This was done to address whether vaporized PLA was attempting to permeate preferential to its layer line direction.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Scanning Electron Microscope \u0026amp; EDS\u003c/h2\u003e\u003cp\u003eBoth EDS line scans and maps were collected in this work using a Tescan Vega II SEM equipped with an Oltim\u0026reg; Max 65 EDS detector running the AZtecLive software. This EDS detector has a resolution at CK of 46 eV or better at all count rates up to 50,000 cps, this resolution is better for distinguishing light elements. All line scans for this study were recorded with an accelerative voltage of 30 kV, working distances of 11.5\u0026ndash;12 mm, and 100x magnification. At this magnification each sample required a series of 19 line scans to reach the full length of each sample, with two or three windows being necessary for one internal line scan. Each line scan window was recorded as a five-line array, spanning approximately 0.75 mm. All line arrays were averaged together by element every 4.4 \u0026micro;m then stitched together and smoothed with a fifth order Savitzky-Golay filter to create the full-length line. Seven EDS maps were also measured at equal increments along the length of a sample at 100x and 500x to be compared to the full-length line scan to determine if the line scan arrays were sufficiently capturing bulk material composition. Internal cross-section line scans were performed after cutting the samples into six segments. Section line scans were collected with identical SEM parameters and measured through each section\u0026rsquo;s center in two directions, parallel and perpendicular to the original layer lines. The layout of all EDS scans can be seen visually in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, all cross-section cuts have been given a letter designation for future reference.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results \u0026 Discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Produced Samples\u003c/h2\u003e\u003cp\u003eExamples of both sample conditions can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, with a clearly oxidized region on the left side of the contaminated sample, however both have visible pores throughout their full lengths. Each sample can also be seen to have discoloration around its edges where polishing did not remove portions of the sintering ballast which adhered to the samples during sintering. Artifacts from these areas will be visible in later EDS scans and will be disregarded for final composition results. Edge defects being so prevalent in these samples exemplifies the need for FFF components to be printed oversized as the exterior surfaces will need significant cleaning following the post processing phases.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eDifferences between conditions are also apparent on the internal cross sections of each sample, some of which are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Images were recorded at an average of 6.0 mm from the contaminated end (and equivalent end of control samples), and 7.0 mm from the opposite end (noncontaminated) of each sample. Image cross section labels are in reference to those shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. It can be seen from these cross sections that, regardless of condition or location, little necking of metal powder particles occur given that borders between particles are clearly discernible throughout the sample. This is especially true for regions of porosity, which based on presences of carbon content spikes shown later are results of trapped PLA, have contaminants preventing sintering between powder particles. It has been shown by Jiang et al. that this material can experience improved sintering with reduced porosity be utilizing higher temperatures during sintering [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Internal porosity appeared to be highly directional in line with the printing layer orientation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Length Scan Results\u003c/h2\u003e\u003cp\u003eGiven the resolutions of the full-length line scans, large variations in data are present from data points collected on metal powder particles, between particles, on pores, etc. An example of the original collected data overlayed by its Savitsky-Golay smoothed line is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, only smoothed lines will be presented in the remaining figures. Comparing the set of seven recorded surface EDS maps plotted in a series alongside its equivalent line scan in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e, we see both scanning methods are nearly identical, even when looking at a light element.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eRegions of intentional contamination were clearly present within the EDS full length scans. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e compares the oxygen content of all six samples by their condition, where the oxygen is exceptionally high in the first portions of the contaminated samples while the control samples are consistent over their length. However, the contaminated samples converge to the same oxygen content as the control samples.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAlong with this increase in oxygen content, the majority of metallic element content reduced when given as a weight percent given the large increase in oxygen. However, iron saw a significant increase coupled with oxygen. Profiles of the three primary alloying elements are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e along with carbon, which is present in a substantial quantity at greater than 10 wt% over the length of all samples. One explanation for the increase in iron wt% seen in areas exposed to excessive oxygen is provided by Xu et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], where Ni-based alloys containing high iron and low aluminum contents exhibit high mass gain from iron-rich oxide scale formation, even in an alloy containing far greater chromium content than was present in our study\u0026rsquo;s material.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs previously mentioned, the excessive amount of carbon present within this material could be a result of residual material from PLA degradation, or an inability for the degraded PLA to escape from within the present metal powder. Multiple lines visible in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e exhibit sample edge effects mentioned previously regarding Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Cross Section Scan Results\u003c/h2\u003e\u003cp\u003eSignificant porosity, visible in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, was present within all contaminated and control specimens, resulting in a high quantity of content variation on the cross-section surfaces. Cross section line scans can again be seen to have the edge contents of the samples that are from sintering ballast residue. Figures\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e and \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e show element content profiles across the centers of cross sections B and F, respectively.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOxygen content remains the primary difference between contaminated and control samples within these scans with two distinct levels of content present within Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ea, which as before is coupled with an increase in iron content. In comparison to the cross sections at the opposite end of the samples in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, the content of the two samples conditions has equalized. Looking closely at the oxygen content of both cross sections, there seems to be a slight increase in content towards the center of the specimens while carbon content remains at a similar level through the thickness. However, comparing the carbon content of the two cross sections with the full-length line scans, there is a higher concentration of carbon within the specimens as compared to on the surface, especially in regard to the control samples. This reduction in oxygen towards the exterior of the sample with the constant level of carbon would lend itself to the conclusion that vaporized PLA is escaping the material more efficiently at the outside of the samples, but a carbon residual is left behind from the degradation itself regardless of depth.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Resulting Composition Comparison\u003c/h2\u003e\u003cp\u003eWith the filament manufacturers provided SDS for the Ni718/PLA filament, a final composition of fully debound material can be estimated. Values for each element were found assuming no residual material from PLA remained after sintering, and by taking equal ratios of each materials initial content ranges provided. These values are compared to this study\u0026rsquo;s EDS findings in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Comparison values from this work were determined by extracting the central 90% of each line scanned from internal cross sections of control samples. The mean weight percents from all internal values were found and scaled proportionally to sum to 100%.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEstimated Content Comparison to EDS Results\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eElement\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFilament SDS\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eEDS Result\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNickel\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e55.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eChromium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIron\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNiobium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.13\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMolybdenum\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.74\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTitanium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAluminum\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCarbon\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOxygen\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9.91\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eResults of the study are clear regarding the excessive quantity of the final material composition of carbon and oxygen reaching almost 30% of the final material weight. This undesirable composition coupled with the clear porosity and lack of sintering shown back in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, one would expect an exceptionally low strength material, which is generally not an expectation of a Ni-based alloy.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study establishes clear expectations for FFF Ni718 bound with PLA when thermally processed in ambient conditions. While the FFF method can produce custom geometries, it does have limitations resulting from the post processing requirements. Thermal processing of metals at high temperatures provides the challenge of dealing with oxidation, an issue which can be amplified by introducing a polymer throughout the material which will need to vaporize. This work showed that shielding materials during sintering can reduce the oxidation of Ni718 during ambient thermal processes, but the resulting material still contains almost 30% of unwanted carbon and oxygen. Manufacturing with metal FFF also necessitates the oversizing of parts before printing to account for shrinkage as a result of sintering and surface cleaning, as surface contaminants of this study are clearly present even after moderate surface polishing.\u003c/p\u003e\u003cp\u003eSamples produced in this study also exhibited little powder particle necking, while it is uncertain if this is a result of the contamination or sintering and debinding schedules. Utilizing inert atmospheres during thermal debinding could be a beneficial process improvement for this material [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], however, it is evident that portions of the contaminating elements are present regardless of excessive oxygen and are instead caused by the PLA degradation. Though these potential improvements are contradictory towards an affordable metal FFF method. Previously mentioned work conducted by Xu et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] found that using a Ni-based alloy with lower iron and higher aluminum content saw a significant reduction in mass gain from oxidization at elevated temperatures. Given the present processing parameters suggested for this study\u0026rsquo;s Ni718, it would be difficult for this material to fulfil its high-strength applications, though this would still need verification though mechanical testing. Iron is also used in Ni718 to improve workability [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], which would not be as necessary for an AM application. Utilizing a different Ni-based alloy could greatly improve the viability of this affordable AM method to produce components for critical applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompeting Interests:\u003c/h2\u003e\u003cp\u003eThe authors have no competing interests to declare that are relevant to the content of this article.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eNo funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e\u003cp\u003eThe authors would like to thank Ohio University\u0026rsquo;s Physics \u0026amp; Astronomy Department for the use of their Scanning Electron Microscope.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGibson, I., Rosen, D., Stucker, B., and Khorasani, M., 2021, \u003cem\u003eAdditive Manufacturing Technologies\u003c/em\u003e, Springer International Publishing, Cham. https://doi.org/10.1007/978-3-030-56127-7.\u003c/li\u003e\n\u003cli\u003eHamidi, M. F. F. A., Harun, W. S. W., Samykano, M., Ghani, S. A. C., Ghazalli, Z., Ahmad, F., and Sulong, A. B., 2017, \u0026ldquo;A Review of Biocompatible Metal Injection Moulding Process Parameters for Biomedical Applications,\u0026rdquo; Materials Science and Engineering: C, \u003cstrong\u003e78\u003c/strong\u003e, pp. 1263\u0026ndash;1276. https://doi.org/10.1016/j.msec.2017.05.016.\u003c/li\u003e\n\u003cli\u003eRamazani, H., and Kami, A., 2022, \u0026ldquo;Metal FDM, a New Extrusion-Based Additive Manufacturing Technology for Manufacturing of Metallic Parts: A Review,\u0026rdquo; Prog Addit Manuf, \u003cstrong\u003e7\u003c/strong\u003e(4), pp. 609\u0026ndash;626. https://doi.org/10.1007/s40964-021-00250-x.\u003c/li\u003e\n\u003cli\u003eDownard, S., Clark, E., O\u0026rsquo;Brien, C., Mohammadlou, B. S., Kontsos, A., Celli, D., Smith, L., Al Amiri, E., Weems, A., and Wisner, B., 2024, \u0026ldquo;Influence of a Suboptimal Environment and Sintering Temperature on the Mechanical Properties of Fused Filament Fabricated Copper,\u0026rdquo; Int J Adv Manuf Technol, \u003cstrong\u003e135\u003c/strong\u003e(7\u0026ndash;8), pp. 3129\u0026ndash;3146. https://doi.org/10.1007/s00170-024-14697-z.\u003c/li\u003e\n\u003cli\u003eGong, H., Snelling, D., Kardel, K., and Carrano, A., 2019, \u0026ldquo;Comparison of Stainless Steel 316L Parts Made by FDM- and SLM-Based Additive Manufacturing Processes,\u0026rdquo; JOM, \u003cstrong\u003e71\u003c/strong\u003e(3), pp. 880\u0026ndash;885. https://doi.org/10.1007/s11837-018-3207-3.\u003c/li\u003e\n\u003cli\u003eThompson, Y., Gonzalez-Gutierrez, J., Kukla, C., and Felfer, P., 2019, \u0026ldquo;Fused Filament Fabrication, Debinding and Sintering as a Low Cost Additive Manufacturing Method of 316L Stainless Steel,\u0026rdquo; Additive Manufacturing, \u003cstrong\u003e30\u003c/strong\u003e, p. 100861. https://doi.org/10.1016/j.addma.2019.100861.\u003c/li\u003e\n\u003cli\u003eTedla, G., Jarabek, A. M., Byrley, P., Boyes, W., and Rogers, K., 2022, \u0026ldquo;Human Exposure to Metals in Consumer-Focused Fused Filament Fabrication (FFF)/ 3D Printing Processes,\u0026rdquo; Science of The Total Environment, \u003cstrong\u003e814\u003c/strong\u003e, p. 152622. https://doi.org/10.1016/j.scitotenv.2021.152622.\u003c/li\u003e\n\u003cli\u003eArrizubieta, J. I., Ukar, O., Ostolaza, M., and Mugica, A., 2020, \u0026ldquo;Study of the Environmental Implications of Using Metal Powder in Additive Manufacturing and Its Handling,\u0026rdquo; Metals, \u003cstrong\u003e10\u003c/strong\u003e(2), p. 261. https://doi.org/10.3390/met10020261.\u003c/li\u003e\n\u003cli\u003eJacobson, M., Cooper, A. R., and Nagy, J., 1964, \u0026ldquo;Explosibility of Metal Powders,\u0026rdquo; United States Department of the Interior, Bureau of Mines\u003c/li\u003e\n\u003cli\u003eJacob, J., Pejak Simunec, D., Kandjani, A. E. Z., Trinchi, A., and Sola, A., 2024, \u0026ldquo;A Review of Fused Filament Fabrication of Metal Parts (Metal FFF): Current Developments and Future Challenges,\u0026rdquo; Technologies, \u003cstrong\u003e12\u003c/strong\u003e(12), p. 267. https://doi.org/10.3390/technologies12120267.\u003c/li\u003e\n\u003cli\u003eLotfizarei, Z., Mostafapour, A., Barari, A., Jalili, A., and Patterson, A. E., 2023, \u0026ldquo;Overview of Debinding Methods for Parts Manufactured Using Powder Material Extrusion,\u0026rdquo; Additive Manufacturing, \u003cstrong\u003e61\u003c/strong\u003e, p. 103335. https://doi.org/10.1016/j.addma.2022.103335.\u003c/li\u003e\n\u003cli\u003eKurose, T., Abe, Y., Santos, M. V. A., Kanaya, Y., Ishigami, A., Tanaka, S., and Ito, H., 2020, \u0026ldquo;Influence of the Layer Directions on the Properties of 316L Stainless Steel Parts Fabricated through Fused Deposition of Metals,\u0026rdquo; Materials, \u003cstrong\u003e13\u003c/strong\u003e(11), p. 2493. https://doi.org/10.3390/ma13112493.\u003c/li\u003e\n\u003cli\u003eMoritzer, E., and Elsner, C. L., 2022, \u0026ldquo;Investigation and Improvement of Processing Parameters of a Copper-Filled Polymer Filament in Fused Filament Fabrication as a Basis for the Fabrication of Low-Porosity Metal Parts,\u0026rdquo; Macromolecular Symposia, \u003cstrong\u003e404\u003c/strong\u003e(1), p. 2100390. https://doi.org/10.1002/masy.202100390.\u003c/li\u003e\n\u003cli\u003eMathesius, M. B., Kozak, E., Scott-Emuakpor, O., and Siddiqui, S. F., 2025, \u0026ldquo;Investigating the Viability of Material Extrusion Additive Manufacturing of Inconel 718 for Fatigue Driven Applications,\u0026rdquo; \u003cem\u003eAIAA SCITECH 2025 Forum\u003c/em\u003e, American Institute of Aeronautics and Astronautics, Orlando, FL. https://doi.org/10.2514/6.2025-1365.\u003c/li\u003e\n\u003cli\u003eThompson, Y., Zissel, K., F\u0026ouml;rner, A., Gonzalez-Gutierrez, J., Kukla, C., Neumeier, S., and Felfer, P., 2022, \u0026ldquo;Metal Fused Filament Fabrication of the Nickel-Base Superalloy IN 718,\u0026rdquo; J Mater Sci, \u003cstrong\u003e57\u003c/strong\u003e(21), pp. 9541\u0026ndash;9555. https://doi.org/10.1007/s10853-022-06937-y.\u003c/li\u003e\n\u003cli\u003eGonzalez-Gutierrez, J., Godec, D., Kukla, C., Schlauf, T., Burkhardt, C., and Holzer, C., 2017, \u003cem\u003eSHAPING, DEBINDING AND SINTERING OF STEEL COMPONENTS VIA FUSED FILAMENT FABRICATION\u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eLou, J., Liu, M., He, H., Wang, X., Li, Y., Ouyang, X., and An, C., 2020, \u0026ldquo;Investigation of Decarburization Behaviour during the Sintering of Metal Injection Moulded 420 Stainless Steel,\u0026rdquo; Metals, \u003cstrong\u003e10\u003c/strong\u003e(2), p. 211. https://doi.org/10.3390/met10020211.\u003c/li\u003e\n\u003cli\u003eLu, Z., Ayeni, O. I., Yang, X., Park, H.-Y., Jung, Y.-G., and Zhang, J., 2020, \u0026ldquo;Microstructure and Phase Analysis of 3D-Printed Components Using Bronze Metal Filament,\u0026rdquo; J. of Materi Eng and Perform, \u003cstrong\u003e29\u003c/strong\u003e(3), pp. 1650\u0026ndash;1656. https://doi.org/10.1007/s11665-020-04697-x.\u003c/li\u003e\n\u003cli\u003eJiang, C.-P., Masrurotin, M., Ramezani, M., Wibisono, A. T., Toyserkani, E., and Macek, W., 2024, \u0026ldquo;Sintering Parameter Investigation for Bimetallic Stainless Steel 316L/Inconel 718 Composite Printed by Dual-Nozzle Fused Deposition Modeling,\u0026rdquo; RPJ, \u003cstrong\u003e30\u003c/strong\u003e(8), pp. 1624\u0026ndash;1637. https://doi.org/10.1108/rpj-04-2024-0163.\u003c/li\u003e\n\u003cli\u003eGreene, G. A., and Finfrock, C. C., 2001, \u0026ldquo;Oxidation of Inconel 718 in Air at High Temperatures,\u0026rdquo; Oxidation of Metals, \u003cstrong\u003e55\u003c/strong\u003e(5), pp. 505\u0026ndash;521. https://doi.org/10.1023/A:1010359815550.\u003c/li\u003e\n\u003cli\u003eXu, Y., Gu, Y., Yan, J., and Sun, F., 2017, \u0026ldquo;Oxidation Behavior of Ni-Based Alloys: Effect of Alloying Additions,\u0026rdquo; Corrosion, \u003cstrong\u003e73\u003c/strong\u003e(3), pp. 247\u0026ndash;255. https://doi.org/10.5006/2192.\u003c/li\u003e\n\u003cli\u003e\u0026ldquo;Is Scanning Electron Microscopy/Energy Dispersive X‐ray Spectrometry (SEM/EDS) Quantitative?\u0026rdquo; https://doi.org/10.1002/sca.21041.\u003c/li\u003e\n\u003cli\u003eRaza, M., Ahmad, F., MUHAMAD, N., Bakar, A., Omar, mohd afian, Akhtar, M., Aslam, M., and SHERAZI, I., 2017, \u0026ldquo;Effects of Debinding and Sintering Atmosphere on Properties and Corrosion Resistance of Powder Injection Molded 316 L - Stainless Steel,\u0026rdquo; Sains Malaysiana, \u003cstrong\u003e46\u003c/strong\u003e, pp. 285\u0026ndash;293. https://doi.org/10.17576/jsm-2017-4602-13.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Additive Manufacturing, Ni718, Fused Filament Fabrication, Metal Injection Molding, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy","lastPublishedDoi":"10.21203/rs.3.rs-7246505/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7246505/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFused filament fabrication (FFF) has become an increasingly popular method for private consumers given its low capital cost. With the development of metal-polymer feedstock material, which can theoretically provide anyone with access to metal components with complex geometry at no machining costs, it is an attractive option. This is especially true for metal alloys that are difficult to produce and used in high end applications such as Ni718. However, the nature of a simple FFF manufacturing process may inhibit the benefits of using such material and must be taken into consideration. This work provides clear expectations of an exceptionally low-cost FFF method to produce Ni718 using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive X-ray Spectroscopy (EDS) to visually evaluate the sintering quantity of the produced material and quantify the final material\u0026rsquo;s chemical composition. Results show that the final composition contains nearly 30% unwanted content by weight with little particle necking or sintering taking place limiting the use cases for such a material system.\u003c/p\u003e","manuscriptTitle":"Material Composition and Sintering Behavior of PLA Bound Ni718 in Ambient Conditions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-13 05:28:19","doi":"10.21203/rs.3.rs-7246505/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2025-10-28T11:22:11+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-10-06T17:43:26+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-01T13:14:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-01T00:48:12+00:00","index":"","fulltext":""},{"type":"submitted","content":"The International Journal of Advanced Manufacturing Technology","date":"2025-07-29T16:14:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ba3c7e45-021a-4e7c-8045-f6b63a13f642","owner":[],"postedDate":"August 13th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T16:01:11+00:00","versionOfRecord":{"articleIdentity":"rs-7246505","link":"https://doi.org/10.1007/s00170-025-16944-3","journal":{"identity":"the-international-journal-of-advanced-manufacturing-technology","isVorOnly":false,"title":"The International Journal of Advanced Manufacturing Technology"},"publishedOn":"2025-11-13 15:57:43","publishedOnDateReadable":"November 13th, 2025"},"versionCreatedAt":"2025-08-13 05:28:19","video":"","vorDoi":"10.1007/s00170-025-16944-3","vorDoiUrl":"https://doi.org/10.1007/s00170-025-16944-3","workflowStages":[]},"version":"v1","identity":"rs-7246505","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7246505","identity":"rs-7246505","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}