Solidification

Ohno, Atsumi

doi:10.1007/978-3-642-95537-2

Cited by 61 publications

(15 citation statements)

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“…Ohno presented similar, though more qualitative, Al Á/Cu alloy experiments [9]. The rate and manner by which free equiaxed grains settle influence the amount and distribution of macrosegregation.…”

Section: Introductionmentioning

confidence: 79%

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Rerko

Groh

Beckermann

2003

Materials Science and Engineering: A

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Macrosegregation in metal casting can be caused by thermal and solutal melt convection, and the transport of unattached solid crystals. These free grains can be a result of, for example, nucleation in the bulk liquid or dendrite fragmentation. In an effort to develop a comprehensive numerical model for the casting of alloys, an experimental study has been conducted to generate benchmark data with which such a solidification model could be tested. The specific goal of the experiments was to examine equiaxed solidification in situations where sinking of grains is (and is not) expected. The objectives were: (1) experimentally study the effects of solid transport and thermosolutal convection on macrosegregation and grain size distribution patterns; and (2) provide a complete set of controlled thermal boundary conditions, temperature data, segregation data, and grain size data, to validate numerical codes. The alloys used were Al Á/1wt.% Á/Cu, and Al Á/10wt.% Á/Cu with various amounts of the grain refiner TiB 2 added. Cylindrical samples were either cooled from the top, or the bottom. Several trends in the data are apparent and provide good starting points for comparisons to numerical models. #

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Section: Introductionmentioning

confidence: 79%

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Rerko

Groh

Beckermann

2003

Materials Science and Engineering: A

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“…The WC samples were created using a continuous casting system (heated mould continuous casting 13 ), in which the molten Al-Si alloy is fed into the graphite mould continuously, after which the alloy is solidified by water droplets just outside of the mould, as seen in Fig. 1c.…”

Section: Methodsmentioning

confidence: 99%

Crystallisation characteristics of primary silicon particles in cast hypereutectic Al–Si alloy

Okayasu

Takeuchi

Shiraishi

2013

International Journal of Cast Metals Research

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The crystallisation characteristics of primary silicon particles in a cast hypereutectic Al-Si alloy were examined using various casting processes. The size of the primary silicon particles depends on the cooling rate. However, the primary silicon particles cannot be crystallised completely when the cooling rate is .20 K s 21 , since uncrystallised Si atoms migrate to the regions at low cooling rates, producing large primary Si particles. Moreover, turbulent metal flow under conditions of high cooling rate leads to the macrosegregation of the primary Si particles, resulting in poor mechanical properties. From the crystallisation characteristics obtained, a suitable solidification criterion can be proposed.

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“…The increase in the strength of convection streams increases the rate of separated free crystals from mold wall. [54][55][56][57] These free crystals may float into hotter regions in the liquid zone or may remelt again based on the temperature gradient and the strength of convection streams. [54][55][56] However, the magnitudes of superheat and casting speed control the level of free metallostatic head ''FMH'' in the liquid zone is shown in Figure 12(a).…”

Section: A Mechanism Of Extruded Surface Segregation Layermentioning

confidence: 99%

Modeling of Heat Transfer and Interdendritic Strain for Exuded Surface Segregation Layer in the Direct Chill Casting of Aluminum Alloys

El-Bealy

2015

Metall Mater Trans B

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This investigation on the formation of exuded surface segregation layer ''ESSL'' is intended to provide experimental and simulated comparison to verify the model developed previously by El-Bealy. Preliminary verification and calibration of the previous 2D mathematical model are demonstrated by quantitative errors between the previous measurements and predictions of temperature and macrosegregation. Also, the results from these comparisons reveal that the errors are in the reasonable and within allowable limits. These comparisons lead to the fact that the exuded surface segregation layer mostly forms on the middle slice of broad sheet ingot face and in the early stages of mold zone. The model predictions point out also that the different interdendritic strain hypotheses associated with fluctuations of mold cooling conditions. This affects the interdendritic liquid flow between the equiaxed crystals which influences the severity of ESSL formation and its macrosegregation level. The mechanism of ESSL with heat flow and interdendritic strain generation has been analyzed and discussed. The quantitative comparisons between the pervious experimental results and numerical simulation in this investigation reveal also several solutions to prevent this defect for future work.

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Solidification

Cited by 61 publications

References 0 publications

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Crystallisation characteristics of primary silicon particles in cast hypereutectic Al–Si alloy

Modeling of Heat Transfer and Interdendritic Strain for Exuded Surface Segregation Layer in the Direct Chill Casting of Aluminum Alloys

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