Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting
Due to elevated temperatures and high vacuum levels in electron beam melting (EBM), spatter formation and accumulation in the feedstock powder, and sublimation of alloying elements from the base feedstock powder can affect the feedstock powder’s reusability and change the alloy composition of fabric...
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MDPI AG
2021-10-01
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| Online Access: | https://www.mdpi.com/1996-1944/14/20/5953 |
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| author | Ahmad Raza Eduard Hryha |
| author_facet | Ahmad Raza Eduard Hryha |
| author_sort | Ahmad Raza |
| collection | DOAJ |
| description | Due to elevated temperatures and high vacuum levels in electron beam melting (EBM), spatter formation and accumulation in the feedstock powder, and sublimation of alloying elements from the base feedstock powder can affect the feedstock powder’s reusability and change the alloy composition of fabricated parts. This study focused on the experimental and thermodynamic analysis of spatter particles generated in EBM, and analyzed sublimating alloying elements from Alloy 718 during EBM. Heat shields obtained after processing Alloy 718 in an Arcam A2X plus machine were analyzed to evaluate the spatters and metal condensate. Comprehensive morphological, microstructural, and chemical analyses were performed using scanning electron microscopy (SEM), focused ion beam (FIB), and energy dispersive spectroscopy (EDS). The morphological analysis showed that the area coverage of heat shields by spatter increased from top (<1%) to bottom (>25%), indicating that the spatter particles had projectile trajectories. Similarly, the metal condensate had a higher thickness of ~50 μm toward the bottom of the heat shield, indicating more significant condensation of metal vapors at the bottom. Microstructural analysis of spatters highlighted that the surfaces of spatter particles sampled from the heat shields were also covered with condensate, and the thickness of the deposited condensate depended on the time of landing of spatter particles on the heat shield during the build. The chemical analysis showed that the spatter particles had 17-fold higher oxygen content than virgin powder used in the build. Analysis of the metalized layer indicated that it was formed by oxidized metal condensate and was significantly enriched with Cr due to its higher vapor pressure under EBM conditions. |
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| format | Article |
| id | doaj.art-f7b579862bce4ab38b47a72a8af06e9c |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T06:26:29Z |
| publishDate | 2021-10-01 |
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| spelling | doaj.art-f7b579862bce4ab38b47a72a8af06e9c2023-11-22T18:56:35ZengMDPI AGMaterials1996-19442021-10-011420595310.3390/ma14205953Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam MeltingAhmad Raza0Eduard Hryha1Department of Industrial and Materials Science, Chalmers University of Technology, SE-412 96 Gothenburg, SwedenDepartment of Industrial and Materials Science, Chalmers University of Technology, SE-412 96 Gothenburg, SwedenDue to elevated temperatures and high vacuum levels in electron beam melting (EBM), spatter formation and accumulation in the feedstock powder, and sublimation of alloying elements from the base feedstock powder can affect the feedstock powder’s reusability and change the alloy composition of fabricated parts. This study focused on the experimental and thermodynamic analysis of spatter particles generated in EBM, and analyzed sublimating alloying elements from Alloy 718 during EBM. Heat shields obtained after processing Alloy 718 in an Arcam A2X plus machine were analyzed to evaluate the spatters and metal condensate. Comprehensive morphological, microstructural, and chemical analyses were performed using scanning electron microscopy (SEM), focused ion beam (FIB), and energy dispersive spectroscopy (EDS). The morphological analysis showed that the area coverage of heat shields by spatter increased from top (<1%) to bottom (>25%), indicating that the spatter particles had projectile trajectories. Similarly, the metal condensate had a higher thickness of ~50 μm toward the bottom of the heat shield, indicating more significant condensation of metal vapors at the bottom. Microstructural analysis of spatters highlighted that the surfaces of spatter particles sampled from the heat shields were also covered with condensate, and the thickness of the deposited condensate depended on the time of landing of spatter particles on the heat shield during the build. The chemical analysis showed that the spatter particles had 17-fold higher oxygen content than virgin powder used in the build. Analysis of the metalized layer indicated that it was formed by oxidized metal condensate and was significantly enriched with Cr due to its higher vapor pressure under EBM conditions.https://www.mdpi.com/1996-1944/14/20/5953electron beam meltingspatter formationsublimationmetalizationoxidationmetal powder |
| spellingShingle | Ahmad Raza Eduard Hryha Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting Materials electron beam melting spatter formation sublimation metalization oxidation metal powder |
| title | Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting |
| title_full | Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting |
| title_fullStr | Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting |
| title_full_unstemmed | Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting |
| title_short | Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting |
| title_sort | characterization of spatter and sublimation in alloy 718 during electron beam melting |
| topic | electron beam melting spatter formation sublimation metalization oxidation metal powder |
| url | https://www.mdpi.com/1996-1944/14/20/5953 |
| work_keys_str_mv | AT ahmadraza characterizationofspatterandsublimationinalloy718duringelectronbeammelting AT eduardhryha characterizationofspatterandsublimationinalloy718duringelectronbeammelting |