Multiscale Simulation of the Effect of Axial Magnetic Field on Macrosegregation and Solidification Structure During Vacuum Arc Remelting of TC17

The effects of axial magnetic field on the macrosegregation and microstructure in vacuum arc remelted ingots of titanium alloy TC17 are investigated by a multiscale modelling approach which combines macroscale transport model with a mesoscale cellular automation model. The results show that with the increase in the intensity or reversal time of the axial magnetic field, the enhanced melt swirl drives a stronger second flow in the vertical plane, which is downward along the sidewall of melting pool and upward in the centerline. When such flow in vertical plane evenly matches with the flow driven by the self-induced Lorentz force, the macrosegregation in the ingot is the weak. Moreover, it is found that the columnar grain structure changes to fine equiaxed grain with the increase in the in the intensity or reversal time of the axial magnetic field.