Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders
Laser direct energy deposition (L-DED) is one of the most promising additive manufacturing methods, which has been paid more and more attention in recent years. An improved heat and mass transfer model was developed here to analyze thermal behavior, driving force, surface tension-driven flow and its...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-05-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/12/5/842 |
| _version_ | 1797497842508496896 |
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| author | Zhiyong Li Gang Yu Xiuli He Shaoxia Li Zhuang Shu |
| author_facet | Zhiyong Li Gang Yu Xiuli He Shaoxia Li Zhuang Shu |
| author_sort | Zhiyong Li |
| collection | DOAJ |
| description | Laser direct energy deposition (L-DED) is one of the most promising additive manufacturing methods, which has been paid more and more attention in recent years. An improved heat and mass transfer model was developed here to analyze thermal behavior, driving force, surface tension-driven flow and its correlation with dilution during L-DED of Co-based powders to a 38MnVS substrate. Thermal behavior was firstly studied for its fundamental influence on fluid flow and mass transfer. Next, the roles of capillary force and thermal capillary force were characterized using both the dimensional analysis and simulation methods, and the mechanism of surface tension-driven flow was also qualitatively investigated. Finally, flow characteristics inside the melt pool were studied in detail and their correlation with the dilution phenomenon was analyzed based on the multi-component mass transfer model. The temperature gradient was found to be much larger at the front of the melt pool, and it took about 200 ms for the melt pool to reach a quasi-steady condition. Moreover, sharp changes in the curvature of the solid/liquid boundary were observed. Surface tension was demonstrated as the main driver for fluid flow and resulted in centrally outward Marangoni flow. Capillary force contributes to the reduction of the curvature of the free surface, and thermal capillary force (Marangoni force) dominated the Marangoni convection. Alloy elements from the powders, such as Co and Ni, were added to the front part of the melt pool and mainly diluted at the upper side of the rear region near the symmetric plane of the melt pool. Fundamental results in this work provide a valuable understanding of the surface tension-driven flow and its correlation with concentration dilution during the additive manufacturing process. |
| first_indexed | 2024-03-10T03:25:00Z |
| format | Article |
| id | doaj.art-55f8044e85464db1a1451ae88829417e |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T03:25:00Z |
| publishDate | 2022-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-55f8044e85464db1a1451ae88829417e2023-11-23T12:10:12ZengMDPI AGMetals2075-47012022-05-0112584210.3390/met12050842Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based PowdersZhiyong Li0Gang Yu1Xiuli He2Shaoxia Li3Zhuang Shu4Wide Range Flight Engineering Science and Application Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaWide Range Flight Engineering Science and Application Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaWide Range Flight Engineering Science and Application Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaWide Range Flight Engineering Science and Application Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaWide Range Flight Engineering Science and Application Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaLaser direct energy deposition (L-DED) is one of the most promising additive manufacturing methods, which has been paid more and more attention in recent years. An improved heat and mass transfer model was developed here to analyze thermal behavior, driving force, surface tension-driven flow and its correlation with dilution during L-DED of Co-based powders to a 38MnVS substrate. Thermal behavior was firstly studied for its fundamental influence on fluid flow and mass transfer. Next, the roles of capillary force and thermal capillary force were characterized using both the dimensional analysis and simulation methods, and the mechanism of surface tension-driven flow was also qualitatively investigated. Finally, flow characteristics inside the melt pool were studied in detail and their correlation with the dilution phenomenon was analyzed based on the multi-component mass transfer model. The temperature gradient was found to be much larger at the front of the melt pool, and it took about 200 ms for the melt pool to reach a quasi-steady condition. Moreover, sharp changes in the curvature of the solid/liquid boundary were observed. Surface tension was demonstrated as the main driver for fluid flow and resulted in centrally outward Marangoni flow. Capillary force contributes to the reduction of the curvature of the free surface, and thermal capillary force (Marangoni force) dominated the Marangoni convection. Alloy elements from the powders, such as Co and Ni, were added to the front part of the melt pool and mainly diluted at the upper side of the rear region near the symmetric plane of the melt pool. Fundamental results in this work provide a valuable understanding of the surface tension-driven flow and its correlation with concentration dilution during the additive manufacturing process.https://www.mdpi.com/2075-4701/12/5/842thermal behaviordriving forcefluid flowmass transferadditive manufacturing |
| spellingShingle | Zhiyong Li Gang Yu Xiuli He Shaoxia Li Zhuang Shu Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders Metals thermal behavior driving force fluid flow mass transfer additive manufacturing |
| title | Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders |
| title_full | Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders |
| title_fullStr | Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders |
| title_full_unstemmed | Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders |
| title_short | Surface Tension-Driven Flow and Its Correlation with Mass Transfer during L-DED of Co-Based Powders |
| title_sort | surface tension driven flow and its correlation with mass transfer during l ded of co based powders |
| topic | thermal behavior driving force fluid flow mass transfer additive manufacturing |
| url | https://www.mdpi.com/2075-4701/12/5/842 |
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