Convection effects and banding structure formation mechanism during directional solidification of peritectic alloys I. Experimental result

Systematic directional solidification experiments were conducted to investigate the convection effects on the banding structure evolution and macrosegregation in nonfaceted-non-faceted model Fe-Ni alloy using conventional resistance heating and induction heating Bridgman directional solidification methods in this paper. It was found that convection can induce severe axial and radial macrosegregation in the directionally solidified samples, and make the microstructures complex and make the steady state difficult to achieve. Axial macrosegregation was reflected in finite samples solidified from the beginning to the end of solidification with the transition from primary phase to peritectic phase. The primary-peritectic transition depended on the alloy composition and convection strength. Radial macrosegregation reflected in the solute concentration poor in the center and rich in edge, and a primary-peritectic transition also exist in the lateral directional from the sample to the edge.