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

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.