DIRECTIONAL SOLIDIFICATION OF A BINARY ALLOY WITH DEFORMED MELT CRYSTAL INTERFACE AND HYDROMAGNETIC EFFECTS

Asymptotic analysis of unidirectional solidification of a binary alloy in the presence of buoyancy and magnetohydrodynamic effects is done for small segregation coefficient and long wave disturbances. We derive an evolution equation which governs the cellular structure of the melt-crystal interface and the binary alloy. This equation incorporates coupled morphological-convective instabilities, buoyancy and hydromagnetic effects. The presence of a vertical magnetic field can promote the onset of cellular structure due to morphological instabilities and leads to an effective segregation which is smaller than the corresponding one in the absence of the vertical magnetic field.