Investigation of thermoelectric magnetic convection and its effect on solidification structure during directional solidification under a low axial magnetic field

Li, Xi; Gagnoud, A.; Ren, Zhongming; Fautrelle, Yves; Moreau, R.

doi:10.1016/j.actamat.2009.01.016

Cited by 95 publications

(40 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our previous work, [10] the TEMC during directional solidification under an axial magnetic field and its effects on the solidification structure were investigated numerically and experimentally. Numerical results indicated that, under an axial magnetic field, the rotatory TEMC around the protruding interface and the tip of the primary arm (cell and dendrite) forms and that the value of the TEMC on different scales is different.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Ren

Gagnoud

et al. 2011

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

This work investigated the thermoelectric magnetic convection (TEMC) during directional solidification under a transverse magnetic field numerically and experimentally. Numerical results show that the TEMC will form in liquid near the liquid/solid interface and in the dendritic network. The value of the TEMC mainly depends on the crucible diameter, the temperature gradient, and the magnetic field intensity. The value of the TEMC increases as the crucible diameter and the temperature gradient are increased. The value of the TEMC on the sample scale increases to a maximum when the magnetic field is of the order of 0.1 T, and then decreases as the magnetic field still increases. However, the value of the TEMC on the cell/ dendrite scale continues to increase with the increase of the magnetic field intensity when the applied magnetic field is less then 1 T. Two alloys are solidified directionally in the vertical configuration under a transverse magnetic field, and results show that the application of a lower transverse magnetic field (B < 1 T) modified the liquid/solid interface shape and the cellular/ dendritic array significantly. Indeed, it was observed that, along with the refinement of the cell/ dendrite, the magnetic field caused the deformation of the liquid/solid interfaces and the extensive segregations (i.e., channel and freckle) in the mushy zone. Comparison of the numerical and experimental results shows that the modification amplitude of the liquid/solid interface and the cellular/dendritic morphology is in good agreement with the value of the TEMC at the liquid/solid interface and in the dendritic network. This implies that changes of the interface shape and the cellular/dendritic morphology should be attributed, respectively, to the TEMC on the sample and the cell/dendrite scales.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Ren

Gagnoud

et al. 2011

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Also, the magnitude of the changes had a material dependency which could be attributed to the variation in thermoelectric power of the various alloys examined. More recently, microstructural changes have been observed over a wide range of magnetic field intensities from low-moderate (O(1T)) field strengths [19][20][21][22] to higher (O(10T)) strengths [23][24][25]. Furthermore, direct in situ observations of solidification under a relatively low magnetic field have shown indications of TEMHD flow at the meso scale [26].…”

Section: Introductionmentioning

confidence: 94%

Analytic Solutions to Determine Critical Magnetic Fields for Thermoelectric Magnetohydrodynamics in Alloy Solidification

Kao

2015

Metall Mater Trans A

View full text Add to dashboard Cite

During alloy solidification, it has been observed that the morphology of microstructures can be altered by applying an external DC magnetic field. This structural change can be attributed to solutal convective transport introduced by Thermoelectric Magnetohydrodynamics (TEMHD) which drives fluid motion within the inter-dendritic region. Complex numerical models with grid resolutions on the microscopic scale have been constructed to solve the equations governing TEMHD. To complement these computationally intensive numerical models, analytic solutions were sought. Specifically, the analytic solutions presented herein are asymptotic solutions derived for TEMHD under low and high magnetic field intensities. Combination of these asymptotic solutions leads to simple formulae for estimating critical magnetic fields which can be readily evaluated in terms of characteristic lengths of materials that have been identified in experiments as key parameters of critical fields. Indeed, the critical magnetic fields predicted with the asymptotic solutions exhibit magnitudes consistent with those applied in current ongoing experiments where significant changes in microstructure have been observed. The capability to predict accurate results indicates that the analytic solutions described herein are valuable precusors not only for detailed numerical simulations but also for experimental design to study critical magnetic fields in alloy solidification.

show abstract

“…The application of an external magnetic field to a solidifying alloy has been experimentally observed to have a significant effect on microstructural evolution [1, 2,3,4,5,6,7,8,9,10,11]. These changes can be attributed to convective transport of solute by Thermoelectric Magnetohydrodynamics (TEMHD).…”

Section: Introductionmentioning

confidence: 99%

The effects of Thermoelectric Magnetohydrodynamics in directional solidification under a transverse magnetic field

Kao

Cai

Lee

et al. 2017

Journal of Crystal Growth

View full text Add to dashboard Cite

The mechanism of macrosegregation and modification to dendrite size and spacing from a transverse magnetic field has been modelled through direct numerical simulation. The primary driver for this mechanism was identified as a strong Lorentz force formed in the interdendritic region, which leads to a large scale flow circulation. The microstructure evolution is modified by convective transport of solute and the predicted morphological features compare favourably to experimental data in the literature. The numerical results also give an insight into the magnitude of flow velocities within the interdendritic region.

show abstract

Investigation of thermoelectric magnetic convection and its effect on solidification structure during directional solidification under a low axial magnetic field

Cited by 95 publications

References 21 publications

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Analytic Solutions to Determine Critical Magnetic Fields for Thermoelectric Magnetohydrodynamics in Alloy Solidification

The effects of Thermoelectric Magnetohydrodynamics in directional solidification under a transverse magnetic field

Contact Info

Product

Resources

About