Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process
In this study, the solidification behaviors of Hastelloy X during laser powder bed fusion (LPBF) were deliberately changed by fabricating a sample with constricted geometry. In-situ temperature measurement by a high-speed thermographic camera and part-scale thermal analysis by the finite element met...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-10-01
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| Series: | Materials & Design |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127522006384 |
| _version_ | 1811254871420043264 |
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| author | Masahiro Kusano Makoto Watanabe |
| author_facet | Masahiro Kusano Makoto Watanabe |
| author_sort | Masahiro Kusano |
| collection | DOAJ |
| description | In this study, the solidification behaviors of Hastelloy X during laser powder bed fusion (LPBF) were deliberately changed by fabricating a sample with constricted geometry. In-situ temperature measurement by a high-speed thermographic camera and part-scale thermal analysis by the finite element method revealed that the constricted geometry suppressed thermal diffusion in the building sample, thereby increasing the sample temperature to over 1000 °C and maintaining the temperature at 700–1000 °C throughout the LPBF process. Multi-track thermal analyses also revealed that both the temperature gradient and solidification rate decreased by more than one digit, leading to a three-digit decrease in the cooling rate. Compared to the parts with the usual thermal history, the parts built at such high temperature had larger crystal grains elongated along the building direction, thicker cellular structures, more carbide precipitates, and a reduction of microhardness. From these results, a solidification map was created based on the correlations between the temperature gradient and solidification rate and the microstructures, and the effects of the elevated temperature on the epitaxial grain growth were also discussed. Consequently, it was demonstrated that the solidification behaviors could be controlled directly during the LPBF process without any additional heating mechanism. |
| first_indexed | 2024-04-12T17:14:24Z |
| format | Article |
| id | doaj.art-89f15878e77d44f6b3311301f9dd59d9 |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-04-12T17:14:24Z |
| publishDate | 2022-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-89f15878e77d44f6b3311301f9dd59d92022-12-22T03:23:42ZengElsevierMaterials & Design0264-12752022-10-01222111016Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion processMasahiro Kusano0Makoto Watanabe1Corresponding author.; Research Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047 Ibaraki, JapanResearch Center for Structural Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047 Ibaraki, JapanIn this study, the solidification behaviors of Hastelloy X during laser powder bed fusion (LPBF) were deliberately changed by fabricating a sample with constricted geometry. In-situ temperature measurement by a high-speed thermographic camera and part-scale thermal analysis by the finite element method revealed that the constricted geometry suppressed thermal diffusion in the building sample, thereby increasing the sample temperature to over 1000 °C and maintaining the temperature at 700–1000 °C throughout the LPBF process. Multi-track thermal analyses also revealed that both the temperature gradient and solidification rate decreased by more than one digit, leading to a three-digit decrease in the cooling rate. Compared to the parts with the usual thermal history, the parts built at such high temperature had larger crystal grains elongated along the building direction, thicker cellular structures, more carbide precipitates, and a reduction of microhardness. From these results, a solidification map was created based on the correlations between the temperature gradient and solidification rate and the microstructures, and the effects of the elevated temperature on the epitaxial grain growth were also discussed. Consequently, it was demonstrated that the solidification behaviors could be controlled directly during the LPBF process without any additional heating mechanism.http://www.sciencedirect.com/science/article/pii/S0264127522006384Laser powder bed fusionConstricted sample geometryElevated temperatureHastelloy XSolidification behaviorGrain growth |
| spellingShingle | Masahiro Kusano Makoto Watanabe Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process Materials & Design Laser powder bed fusion Constricted sample geometry Elevated temperature Hastelloy X Solidification behavior Grain growth |
| title | Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process |
| title_full | Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process |
| title_fullStr | Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process |
| title_full_unstemmed | Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process |
| title_short | Microstructure control of Hastelloy X by geometry-induced elevation of sample temperature during a laser powder bed fusion process |
| title_sort | microstructure control of hastelloy x by geometry induced elevation of sample temperature during a laser powder bed fusion process |
| topic | Laser powder bed fusion Constricted sample geometry Elevated temperature Hastelloy X Solidification behavior Grain growth |
| url | http://www.sciencedirect.com/science/article/pii/S0264127522006384 |
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