Highly coercive milled and melt-spun (Pr, Nd)FeB-type magnets and their hot workability

Highly coercive isotropic (Pr1-xNdx)(2)Fe14B-type magnets (0 less than or equal to x less than or equal to 1) have been processed using high energy ball milling and melt-spinning techniques, and an assessment of their hot deformation behavior has been carried out. A very high coercivity of mu H-0(c) = 2.7 T and a remanence of J(r) = 0.72 T were found after annealing partly amorphous Pr15DyFe75.9B8Zr0.1 ribbons. Samples containing Dy (1at.%) and Zr (0.1at.%) exhibit an improved stability against grain growth with increasing the annealing temperature. It has been found that the deformation forces necessary for texturing by hot deformation are the lowest for the as-milled Pr-containing alloys. As-milled Pr15Fe77B has been textured by die-upsetting at 750 degreesC obtaining magnetic properties as high as J(r) = 1.27 T, mu H-0(c) = 1.20T and (BH)(max) = 307 kJ/m(3).