Bulk metallic glass formation, composite, and magnetic properties of Fe-B-Nd based alloys

Abstract

The glass formation in Fe-rich ternary Fe-B-Nd and quaternary (Fe,B,Nd)96Nb4 alloys been studied and the best ternary and quaternary glass formers are located at Fe67B23 Nd10 and (Fe68B25 Nd7)Nb4 with critical diameters of 1 and 4 mm, respectively. For (Fe,B,Nd)96Nb4 alloys, the competing phases with glass were identified by monitoring the microstructure change. Fe14Nd2B was discovered to be one competing phase, which is the principle magnetic phase for Nd-Fe-B hard magnets. Composites with uniformly distributed Fe14Nd2B were fon-ned for quaternary alloys with a diameter of 1.5 to 3 mm. Bulk hard magnets could be obtained by directly annealing the composites in a compositional area. A hard magnet with a coercivity of 1,100 kAm-1 and a maximum energy product, (BH)max, of 33 kJm-3 was obtained at (Fe67B23 Nd10)96Nb4 by annealing. The combination of hard magnetic properties and the large critical sample size may make these alloys a commercially viable candidate for industrial applications. © 2009 Materials Research Society.