Direct crystallization of the peritectic Nd2Fe14B1 phase by undercooling of the melt

Phase selection in undercooled Nd–Fe–B alloy melts has been investigated by electromagnetic levitation experiments with respect to the competitive formation of the peritectic Nd2Fe14B1 phase (φ-phase) and the properitectic γ-Fe solid solution. It is shown that primary solidification of stable γ-Fe is suppressed in favour of the direct crystallization of the peritectic Nd2Fe14B1 intermetallic compound with increasing undercooling. Besides the primary φ-phase, another solidification route of the undercooled melt resulting in a metastable phase is found in a wide range of alloy compositions.