The Marangoni convection effects on directional dendritic solidification

Nabavizadeh, Seyed Amin; Eshraghi, Mohsen; Felicelli, Sergio D.; Tewari, Surendra N.; Grugel, R. N.

doi:10.1007/s00231-019-02799-4

Cited by 10 publications

(8 citation statements)

References 52 publications

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“…Moreover, a consistent picture regarding the impact of directional flow fields on dendrites has not yet emerged: Nguyen-Thi et al found bending to occur in the direction of the flow, away from the feedingelement-rich melt, and toward the colder region [22]. Similar results were obtained by Nabavizadeh et al in simulations [18]. On the other hand, Murakami et al observed the bending of dendrites against the flow direction, toward the hotter region and toward higher feeding-element concentration [45].…”

Section: Bending Of Dendritesmentioning

confidence: 66%

“…Corresponding experiments on a transparent organic succinonitrile-based alloy were performed by Nabavizadeh et al in microgravity aboard the International Space Station, so as to eliminate gravity-driven factors such as convective flow and buoyancy of bubbles. The study concludes that Marangoni flow indeed affects the growth direction of dendrites, causing them to bend away from the bubble [18].…”

Section: Introductionmentioning

confidence: 85%

“…As both parameters cause an increase in surface tension on the dendritefacing side of the bubble, Marangoni vortices will transport Al-rich, hot melt toward the dendrite front. This causes a deviation of the dendrites' growth direction away from the bubble under microgravity conditions, according to Nabavizadeh et al [18].…”

Section: Bending Of Dendritesmentioning

confidence: 95%

“…While the temperature gradient will always cause a flow from the hot side of the bubble to the cold side, the concentration gradient-driven flow depends on the melt compositions and the corresponding surface tension distribution around the bubble. Depending on the thermal/concentrational gradients of the system, the flow vortices can thus transport fluid in either direction for different experimental setups [4,18,42,43].…”

Section: Bending Of Dendritesmentioning

confidence: 99%

“…Under standard gravity, convective effects as well as movement of the bubbles due to buoyancy make it challenging to observe the Marangoni effect on bubble interfaces [18]. As the near-2D setup of the experiment in horizontal position reduces both, convection and buoyancy-effects, Marangoni flow fields may be strong enough to influence the growing microstructure in an observable way.…”

Section: Bending Of Dendritesmentioning

confidence: 99%

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In situ observation of the impact of hydrogen bubbles in Al–Cu melt on directional dendritic solidification

et al. 2021

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Much research has already been focused on the solid-bubble interaction in the interdendritic space for solidifying materials. However, commonly, bubble nucleation is not limited to the mushy zone but also occurs in the liquid melt. In the present research on an Al-$$10 \, \%\mathrm {wt. \,}$$ 10 % wt . Cu alloy, the interaction between these bubbles and the approaching solidification front becomes apparent under in situ X-radiography and allows for new insights into the influence of bubbles on the solidifying microstructure. The observed effects comprise bulging of the solidification front toward the bubble, bending of dendrites in front of the bubble, coronal outgrowths surrounding the bubbles, as well as bubble growth, bubble pushing, and bubble eruption. It is found that for the present Al–Cu alloy, the local variation in the solidification speed can be attributed to the bubbles’ insulating properties. The range of this effect was observed to be up to $$900 \,\upmu \text {m}$$ 900 μ m , depending on the bubble diameter, locally increasing solidification speed by up to $$350 \, \%$$ 350 % . The influences of Marangoni vortices and coronal nucleation of misoriented dendrites around bubbles on the homogeneity of the microstructure are discussed. A comparison with experiments on model alloys and simulations from various other studies highlights the similarities and differences to this metallic alloy system.

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Section: Bending Of Dendritesmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 85%

Section: Bending Of Dendritesmentioning

confidence: 95%