Method of improving toughness of sintered RE-Fe-B-type, rare earth permanent magnets

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Disclosed are methods for producing compositionally modified sintered RE—Fe—B-based rare earth permanent magnets, by the addition of small amounts of Nd, Cu, Ti, Nb, or other transition metals, and mixtures thereof, to maximize fracture toughness with corresponding improved machinability, while maintaining maximum energy product, said method comprising the steps of : (a) prepare a magnetic composition; (b) melt the composition and form powders with an average particle size smaller than 5 microns from the same; (c) press the powder under a magnetic field to obtain green compacts, which are then sintered at from about 1030° C. to 1130° C., and heat treating the sintered material at from about 570° C. to 900° C.