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 (phi-phase) and the properitectic gamma-Fe solid solution. It is shown that primary solidification of stable gamma-Fe is suppressed in favour of the direct crystallization of the peritectic Nd2Fe14B1 intermetallic compound with increasing undercooling. Besides the primary phi-phase, another solidification route of the undercooled melt resulting in a metastable phase is found in a wide range of alloy compositions. (C) 2003 Elsevier B.V. All rights reserved.