Effect of high static magnetic field and AC current on solidification of Zn-30wt% Bi monotectic alloy

Effect of high static magnetic field (HSMF) coupled with AC current of different intensities and frequencies on solidification morphology of Zn-30wt% Bi monotectic alloy was studied. The gravity segregation of Zn-30wt % Bi monotectic alloy could not be suppressed thoroughly only by superimposing AC current or 10 T HSMF separately at the cooling rate of 25 degrees C/min. When the 10 T HSMF and 50 Hz AC current were super-imposed simultaneously, the induced alternate Lorentz force could reduce the gravity segregation remarkably. More homogeneous solidification morphology could be obtained when increasing the AC current density, magnetic flux density or current frequency separately. However, each of the above-mentioned three parameters has its own optimum value on deviating from which the homogeneous distribution morphology could not be obtained. The mechanism on the coupled fields affecting the gravity segregation of Zn-30wt% Bi monotectic was discussed based on the magneto-hydrodynamic theory. The results reveal that it is possible to manufacture homogeneous monotectic alloy under normal gravity surroundings and at a low cooling rate by superimposing coupled fields in the solidification process.