The relevance of melt convection to grain refinement in Al–Si alloys solidified under the impact of electric currents

Effect of Direct Current on Microstructure Evolution of Directionally Solidified Sn-70 wt pct Bi Alloy at Different Pulling Rates

“…Various explanations for current treatment have been proposed, such as the increase in the solid-liquid interfacial energy, [16] the suppression of grain growth due to Joule heating, [13] current crowding due to the differing electrical conductivities of solid and liquid, [2] electromigration, [10] melt flow caused by Lorentz force, [2] and the reduction in the nucleation activation energy. [17] Recently, Ra¨biger et al [18] considered that the grain refinement of Al-7 wt pct Si alloy was ascribed solely to the forced melt flow driven by Lorentz force under DC of 50 A. In summary, the previous studies taken together do not provide a consistent picture of structure modification under current.…”

Comparative Study on the Grain Refinement of Al-Si Alloy Solidified under the Impact of Pulsed Electric Current and Travelling Magnetic Field

“…Our recent research has shown that the Lorentz force caused by ECP and its own induced magnetic field can induce the strong forced flow inside melt [21,22], which was also the key effect that caused the grain refinement in alloy [22,23]. Since it is well known that grain refinement under the application of EMS is caused by the forced flow, it indicates that ECP or EMS may cause the same grain refinement process in alloys.…”

“…In our case, the survival of grains can be guaranteed on account of the fact that a In summary, it is clear that the grain refinement driven by ECP and TMF in the employed solidification regime has the same grain refinement occurrence period, during which the refined equiaxed grains are continuously generated. It could be due to the fact that the ECP-or TMF-induced forced flow plays a key role in the grain refinement of alloys [13,22]. According to the fluid mechanics theory [24], any convection can be effectively damped by the high viscosity.…”

Effect of Direct Current on Solid-Liquid Interfacial Tension and Wetting Behavior of Ga–In–Sn Alloy Melt on Cu Substrate

“…Consequently, much of the fundamental research has been performed towards understanding the mechanism behind the modification of the solidification structure by electric current [4][5][6][7]. However, the exact modification mechanism is not fully understood and it is still controversial.…”