| In these experiments, molten samples of three different compositions of tin-bismuth alloys cooled and solidified while exposed to a steady (not alternating), unidirectional magnetic field. Temperature-time curves were recorded as the alloy melts cooled. While the samples cooled, a magnetic field ranging from zero tesla to two tesla (0 T to 2 T) was imposed. The cooling curves were compared and evaluated in terms of the undercoolings required to nucleate the solid phases. Metallography of the ingots revealed structural differences caused by the magnetic field. It appears that the field modified the pattern of convection currents in the solidifying ingot, in accord with observations by other research groups on other alloy systems solidified in a direct-current magnetic field. The effects of the magnetic field on undercoolings are different for different alloy compositions. |
