Die-upset hybrid Pr–Fe–B nanocomposite magnets

Abstract

Anisotropic nanocomposite R–Fe–B/Fe magnets (R=Pr, Tb) were synthesized by hot pressing and subsequent die upsetting blends of R-rich and R-lean melt-spun ribbons. The magnets have a layered structure, in which alternating layers of the two starting alloys lay perpendicularly to the pressing direction. A crystallographic alignment of the R2Fe14B grains is observed in the R-rich layers, whose microstructure is identical to that of the conventional die-upset magnets. The R-lean layers consisting of exchange-coupled R2Fe14B and α-Fe grains retain the random crystallographic orientation. The obtained bulk R-lean magnets show better properties than magnets of the same overall composition prepared from a single alloy.

Magnetic and microstructural study of hybrid magnet consisting of R-rich and R-lean Nd–Fe–B alloys

“…The magnetic alignment indicated by the Mr(//)/Mr(?Þ ratio appears to increase with increasing the deformation rate (height reduction). Microstructural study [1,2] showed that a texture was developed only in the R-rich Nd 2 Fe 14 B single phase alloy region in the die-upset hybrid magnet (Fig. 4).…”

“…The hybrid magnet consisting of the Nd 2 Fe 14 B single phase alloy (called R-rich alloy, hereafter) and the Nd 2 Fe 14 B=Fe nanocomposite alloy (called R-lean alloy) is of interest [1,2]. The hybrid magnet can exploit the merits of the single phase alloy and the nanocomposite alloy: the Nd 2 Fe 14 B single phase alloy guarantees high coercivity and the nanocomposite alloy provides high magnetization.…”

Anisotropy study of hybrid magnet consisting of Nd2Fe14B single phase and nanocomposite alloys

“…The anisotropic nature in the die-upset hybrid magnet is probably due to the texture developed in the Nd 13.5 Fe 80 Ga 0.5 B 6 alloy region during the deformation. It has been reported [5] that in the hybrid magnet a texture was developed only in the Nd 2 Fe 14 B single phase region. The magnetic alignment in the die-upset hybrid magnet appears to be inferior to that of the single alloy counterpart.…”

“…Most of the current nanocomposite materials are virtually isotropic without magnetic alignment. Recently, a unique magnet processing technique, in which the R 2 Fe 14 B/a-Fe nanocomposite (R ¼ Nd, Pr) material was hybridized with Nd 2 Fe 14 B single phase material, was suggested [5,6]. The aim of the present study is to examine the anisotropic nature of the hybrid magnets.…”

Generation and Characterization of Anisotropic Microstructures in Rare Earth-Iron-Boron Alloys

“…However, a challenge still exists to successfully create these in an anisotropic form. Attempts at die-upset [66,67], thick film synthesis [68], chemical deposition [69], hot extrusion [70], and surfactant-assisted high energy ball milling [50] have all been attempted with very limited success. In each case, either the spacing is insufficiently small or the processing route is no longer viable with the alloy.…”