LAUSR

The present work investigates how axial static magnetic field affects the solidification structure and the solute distribution in directionally solidified GCr18Mo steel. Experimental results show that grain refinement and the columnar to equiaxed transition is enhanced with the increases in the magnetic field intensity (B) and temperature gradient (G) and the decrease in the growth speed. This phenomenon is simultaneously accompanied by more uniformly distributed alloying elements. The corresponding numerical simulations verify a thermoelectric (TE) magnetic convection pattern in the mushy zone due to the interaction between the magnetic field and TE current. The TE magnetic convection in the liquid should be responsible for the motion of dendrite fragments. The TE magnetic force acting on the dendrite is one of the driving forces trigging fragmentation.