Anisotropic effect of magnetohydrodynamics on metal solidification.

Abstract

Japan.

Effect of frequency and intensity of rotating magnetic field on the microstructures of Pb-Sn alloys

“…According to eqs. (11) and (14), the Gibbs free energy associated with the formation of critical crystal nucleus and atom diffusing activation energy are reduced with RMF. Eq.…”

“…Eq. (11) shows that the Gibbs free energy associated with the formation of critical crystal nucleus decreases with the increase of the undercooling, which is beneficial to nucleation. Besides, the vibrating frequency [19] of liquid atom in melt is also affected by RMF:…”

“…The refinement of equiaxed crystal is due to the fracture of dendrite arms under electromagnetic stirring. Kishida et al [11] studied the effect of stationary magnetic field on microstructure of Pb-Sn alloy, and found that columnar structure fraction increased with the increase of the magnetic intensity, which made the equiaxed crystal coarsen at the same time. The convection driven by RMF caused a transition of primary phase from columnar-to-equiaxed growth of Pb-Sn alloy [12,13] .…”

Effect of a low axial magnetic field on the primary Al2Cu phase growth in a directionally solidified Al–Cu hypereutectic alloy

“…In the solidification process, the convection at the liquid/solid interface significantly affects the mass, heat transport and crystal growth, which plays a great role in controlling the solidification structure [6,7]. It is well known that natural thermosolutal convection can be suppressed effectively by the magnetic field [8][9][10]; however, numerous works have been performed on the effects of thermoelectric magnetic force (TEMF) and thermoelectromagnetic convection (TEMC) induced by the interaction between Seebeck effect and the magnetic field during directional solidification. These effects affect the convection at the liquid/solid interface, crystal growth and segregation significantly [11][12][13][14][15].…”

Effect of magnetic field on phase morphology transformation of MnO2 nanostructures in a hydrothermal process

“…Though the exact mechanism for the function of pulsed magnetic field is still unclear, it is supposed that the magnetic field hold an important role in the process of MnO 2 nucleation and growth. On the one hand, the pulsed magnetic field, which can offer a periodically applied energy field, can affect the nucleation of MnO 2 by vibrating and breaking the initially formed tiny nuclei into pieces [23,24]. So the nucleation of β-MnO 2 may be interfered and the transformation time is prolonged.…”