Effect of Rare Earth Substitution on Machinability of R-Fe-B Sintered Magnets

The machinability of sintered Nd-Fe-B magnets with nominal compositions of (Nd1–xDyx)16Fe78B6 (x = 0, 0.05, 0.10, 0.15) and (Nd1–yPry)16Fe78B6 (y = 0, 0.33, 0.67, 1), has been investigated. The bending strength, fracture toughness and the Vickers Hardness were measured. It shows that the Dy substituted magnets shows higher Vickers Hardness than the Pr substituted magnets. The brittle index for investigated magnets improves monotonously with increasing Dy content, reduces with increasing Pr content, respectively, which seems to relate closely to the change of the lattice parameters.