Microstructure of peritectic Tb-Dy-Fe alloys after electromagnetic levitation melting

摘要

The electromagnetic levitation melting of the rare earth giant magnetostrictive materials Tb_(0.27) Dy_(0.73) Fe_(1.90) alloys is realized. The compound is difficult to realize levitation melting at terrestrial environment because of its high density and low electric conductivity. The microstructure of the sample near peritectic composition obtained by this process contains REFe_2 matrix phase, a large amount of rod-like REFe_3 phase embedded in the matrix phase, rare earth rich phase enriching around the REFe_3 phase and a small amount of rare earth rich phase in the REFe_2 matrix phase far from the REFe_3 phase, which is significantly different from that of the sample obtained by general melting-casting process with the same composition, which contains almost complete REFe_2 phase and a small amount of RE rich phase in the REFe_2 matrix phase. The formation of the microstructure can be attributed to the coupled growth of the peritectic phase―REFe_2 and the primary phase―REFe_3, and the subsequent eutectic reaction under this experimental condition.