Sulfur-induced transitions of thermal behavior and flow dynamics in laser powder bed fusion of 316L powders

Li, Zhiyong; He, Xiuli; Li, Shaoxia; Kan, Xinfeng; Yin, Yanjun; Yu, Gang

doi:10.1016/j.tsep.2023.102072

Cited by 4 publications

(5 citation statements)

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“…The differences in melt pool dynamics between sulfur free situation and 0.03% sulfur situation are thoroughly discussed and compared in our previsou publication [46]. Some major conclusions are drawn from [46]. The new flow pattern of combined outward-inward flow is observed because of the sulfur-induced transition of surface tension.…”

Section: Resultsmentioning

confidence: 95%

“…Consequently, most of the previous modelling works for LPBF focus on conduction mode. The differences in melt pool dynamics between sulfur free situation and 0.03% sulfur situation are thoroughly discussed and compared in our previsou publication [46]. Some major conclusions are drawn from [46].…”

Section: Resultsmentioning

confidence: 96%

“…Melt pool dynamics in 0.03% sulfur situation are more complex with more vortexes induced at transverse section and more branch flows and mixing positions of branch flow (MPBF) observed at longitudinal section. More detailed comparisons and discussion are presented in reference [46].…”

Section: Resultsmentioning

confidence: 99%

“…Thus, there exists a sulfur concentration threshold, distinguishing between Sul-1 and Sul-2, that determines the occurrence of TCST sign transition. The direction of the flow pattern depends on the sign of TCST because surface tension is the dominant driving force in L-PBF [46]. As depicted in figure 8, three distinct flow patterns correspond to the three TCST types.…”

Section: Thermo-capillarity Transitionmentioning

confidence: 99%

“…Referring to figure 7, the transition temperature of TCST in Sul-2 is 1942 K, whereas in Sul-6, T t is 2590 K. This suggests that the sign Furthermore, it's worth noting that both forward and backward flows are observed in all six scenarios. This bidirectional flow is considered advantageous for promoting the homogeneous mixing of molten powders and the melted substrate [46].…”

Section: Sulfur-effect On Melt Pool Dynamicsmentioning

confidence: 99%

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Impact of sulfur content on thermo-capillarity and melt pool dynamics in laser powder bed fusion of 316L powders

Li,

Kan,

Yin

2023

Mater. Res. Express

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A three-dimensional numerical model is developed to investigate the influence of sulfur content on the transitions of thermo-capillarity and flow dynamics during laser powder bed fusion (LPBF) of 316L powders. The impacts of variations in sulfur contents on thermal behaviors involving heat transfer and solidification characteristics, thermo-capillarity transition, as well as the spatial and directional transitions in flow dynamics, are analyzed through mechanistic modeling techniques. It is observed that transient thermal behaviors, including melt pool profile, track morphology, and solidification processes, are significantly influenced by the contained sulfur concentration. High sulfur concentrations tend to result in finer microstructures and equiaxed grains. Through simulations, it is noted that the transition in the sign of temperature coefficient of surface tension (TCST) is more easily observable in low-sulfur level (0.0001%) but disappears as the sulfur concentration is extremely low. With sulfur content increasing, a more homogenized velocity distribution is observed, accompanied with heightened flow complexity denoted by the emergence of additional branch flows and vortices. These findings offer valuable insights into the underlying physics of melt pool dynamics in the LPBF process and present a potential approach for process optimization.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Thermo-capillarity Transitionmentioning

confidence: 99%

Section: Sulfur-effect On Melt Pool Dynamicsmentioning

confidence: 99%

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