Simultaneous Observation of Melt Flow and Motion of Equiaxed Crystals During Solidification Using a Dual Phase Particle Image Velocimetry Technique. Part II: Relative Velocities

Kharicha, Abdellah; Stefan-Kharicha, Mihaela; Ludwig, Andreas; Wu, Menghuai

doi:10.1007/s11661-012-1415-y

Cited by 11 publications

(8 citation statements)

References 24 publications

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“…The amount of equiaxed crystals was negligible. This is a major difference with the previous observations done under similar experimental conditions (Kharicha et al 2013a(Kharicha et al , 2013b where intense equiaxed crystals occur and freckle formation was observed. Images were recorded every minute and from the direct visualisation (PIV) and a special image treatment we could extract the thickness of the mushy zone, the total mushy fraction and the flow velocity as function of time.…”

Section: Discussioncontrasting

confidence: 99%

“…The growth was very uniform and smooth along the whole length of the walls. No channels formed in the mushy zone, nor chimneys with the release of equiaxed crystals, as in previous publications (Kharicha 2013a(Kharicha , 2013b. However, at 22 min some equiaxed grains formed very close to the lateral walls.…”

Section: Flow Visualisation and Regimessupporting

confidence: 83%

“…The cooling from the walls and the occurrence of solidification generate various and complex phenomena. Regardless of the superheat which was employed, each experiment followed similar flow regimes as described in the previous analysis of Kharicha et al (Kharicha et al 2013a(Kharicha et al , 2013b, where however massive equiaxed crystals were present. Only the time when a regime changes into the next depends on the superheat.…”

Section: Flow Visualisation and Regimesmentioning

confidence: 99%

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Observation of flow regimes and transitions during a columnar solidification experiment

Stefan-Kharicha

Kharicha

et al. 2014

Fluid Dyn. Res.

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Section: Discussioncontrasting

confidence: 99%

Section: Flow Visualisation and Regimessupporting

confidence: 83%

Section: Flow Visualisation and Regimesmentioning

confidence: 99%

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Observation of flow regimes and transitions during a columnar solidification experiment

Stefan-Kharicha

Kharicha

et al. 2014

Fluid Dyn. Res.

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“…It was observed that the crystals settled down during solidification and gradually formed a sedimentation bed on the cavity floor, which was a zone of negative segregation. This phenomenon is further confirmed and characterized through more delicate experiments4041. Both present simulation and these experiments have demonstrated that the motion of crystals due to gravity is common and plays a crucial role on the formation of the macrosegregation pattern.…”

Section: Resultssupporting

confidence: 77%

Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification

Chen

Kang

et al. 2017

Sci Rep

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Motion of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field model incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed model circumvents complexity to resolve dendritic growth, natural convection and solid motion simultaneously. Simulations are performed for single and multiple dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid motion is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer model in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the motion of dendrites accelerates the occurrence of growth impingement which causes the behaviors of multiple dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots.

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“…Shigeo et al [15] used a potassium permanganate dye to trace fluid motion within the sidewall mushy region during a two sides chilling solidification. Kharicha et al [16] used the PIV technique to study the flow pattern and the equiaxed crystal motion during an equiaxed/columnar solidification process. Zhong et al [17] investigated the effect of crystal rain produced from the free surface on columnar to equiaxed transition.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Solidification in the Cast Mold with a Consumable Cooler Introduced Inside

Niu

Liu

et al. 2019

Metals

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The microstructure is of great significance for the stability and mechanical performance of the cast slab. Recently, an innovative technology of feeding a consumable cooler into the mold has been proposed to improve the internal quality of castings. But the mechanism is not clear. In the present work, a water-cooled transparent laboratory equipment was set up and solidification of NH4Cl-70%H2O solution was studied to observe the in-situ growth and sedimentation of crystals. The experiments were conducted with and without adding a consumable cooler. Morphology variation of the solidification structure was visualized and temperature distribution during the process was recorded. Results show that introduction of the consumable cooler significantly reduces the temperature of the central zone. Melting of the consumable cooler can supply a large quantity of equiaxed crystals, which prevent the growth of columnar dendrites and thereby promote columnar to equiaxed transition (CET). Moreover, the enhanced convection shows an effect of grain refinement.

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Simultaneous Observation of Melt Flow and Motion of Equiaxed Crystals During Solidification Using a Dual Phase Particle Image Velocimetry Technique. Part II: Relative Velocities

Cited by 11 publications

References 24 publications

Observation of flow regimes and transitions during a columnar solidification experiment

Observation of flow regimes and transitions during a columnar solidification experiment

Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification

Experimental Investigation of Solidification in the Cast Mold with a Consumable Cooler Introduced Inside

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