EFFECT OF MAGNETIC-FIELD ON THE MICROSTRUCTURE AND MACROSEGREGATION IN DIRECTIONALLY SOLIDIFIED PB-SN ALLOYS

An investigation into the influence of a transverse magnetic field (0. 45 T) on the mushy zone morphology and macrosegregation in directional ly solidified hypoeutectic Pb-Sn alloy shows that the field has no inf luence on the morphology of dendritic arrays. The field does, however, cause severe distortion in the cellular array morphology. Cellular ar rayed growth with the magnetic field results in an extensive channel f ormation in the mushy zone, as opposed to the well-aligned and uniform ly distributed cells formed in the absence of the field. The channels are produced due to the anisotropy in the thermosolutal convection cau sed by the magnetic field. Macrosegregation, however, along the length of the directionally solidified samples is not influenced by this mag netic field for either the cellular or dendritic arrays.