Microstructure of nanocomposite R-Fe-B die-upset magnets (R=Pr,Nd) produced from mechanically milled powders

Microstructure and magnetic properties of die-upset R-Fe-B magnets (R=Nd,Pr) produced from high-energy ball milled powders have been studied. The Nd-Fe-B series alloys had nominal compositions Nd_xFe_93.5-xGa_0.5B₆ (x=14-16), and the Pr-Fe-B series alloys were nominally the stoichiometric Pr₁₂Fe₈₁Ga₁B₆ and Pr₁₂Fe₈₀Cu₁Ga₁B₆ alloys. Results show that a relatively small difference in the rare earth content results in dramatic differences in both the magnetic properties and microstructure of Nd_xFe_93.5-xGa_0.5B₆ magnets. Small amount of Cu addition in Pr-Fe-B alloys promotes the formation of textured microstructure, leading to the increase in magnetic properties.