Thermocapillary (Marangoni) flow in melt pools for additive manufacturing using laser-based powder bed fusion
Nguyen, Nhi (2026)
2026
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2026050810400
https://urn.fi/URN:NBN:fi:amk-2026050810400
Tiivistelmä
Surface quality in laser powder bed fusion (LPBF) depends on melt-pool behaviour because flow and stability in the molten region shape the surface of the printed part. Earlier studies showed that TiO₂-coated 420J2 powder can improve surface quality, but the molten region is difficult to observe during the process. Therefore, this study aims to provide insight into melt-pool behaviour, with a focus on thermocapillary (Marangoni) flow in pure SUS420 and SUS420 with 0.02 wt% TiO₂ nanoparticles.
The study is based on thermal-fluid theory, including heat transfer, laminar flow, phase change, and thermocapillary convection. The research design is a comparative numerical simulation study supported by published experimental results. A COMSOL model compared pure SUS420 and the composite under the conditions.
The results showed that the mixture reached higher temperatures and heat accumulation at scan speeds. Both surface-flow patterns showed thermocapillary-driven circulation, with the TiO₂ mixture showing a more organised flow field. This suggests that TiO₂ nanoparticles can influence heat redistribution and melt-pool flow behaviour, bringing a potential contribution to surface quality improvement. However, not all cases fully reached the melting temperature, limiting melt-pool development. For future work, higher laser power and better optimised scan conditions are needed for more conclusive comparisons.
The study is based on thermal-fluid theory, including heat transfer, laminar flow, phase change, and thermocapillary convection. The research design is a comparative numerical simulation study supported by published experimental results. A COMSOL model compared pure SUS420 and the composite under the conditions.
The results showed that the mixture reached higher temperatures and heat accumulation at scan speeds. Both surface-flow patterns showed thermocapillary-driven circulation, with the TiO₂ mixture showing a more organised flow field. This suggests that TiO₂ nanoparticles can influence heat redistribution and melt-pool flow behaviour, bringing a potential contribution to surface quality improvement. However, not all cases fully reached the melting temperature, limiting melt-pool development. For future work, higher laser power and better optimised scan conditions are needed for more conclusive comparisons.