Back to Search Start Over

Microstructural and magnetic properties of Nd-Fe-B alloys processed by equal-channel angular pressing.

Authors :
Onal, E.
Lapovok, R.
Kishimoto, H.
Kato, A.
Davies, C. H. J.
Suzuki, K.
Source :
Journal of Applied Physics; 2015, Vol. 117 Issue 17, p17A742-1-17A742-4, 4p, 1 Black and White Photograph, 1 Diagram, 3 Graphs
Publication Year :
2015

Abstract

Equal-channel angular pressing (ECAP) is a well-established thermo-mechanical processing technique. This technique allows virtually unlimited strain and manipulation of texture by processing route, while the cross-section of the sample remains unchanged during processing. In order to clarify the effectiveness of ECAP on preparing anisotropic permanent magnets, the microstructure and magnetic properties of a melt-spun Nd<subscript>13.5</subscript>Fe<subscript>73.8</subscript>Co<subscript>6.7</subscript>B<subscript>5.6</subscript>Ga<subscript>0.4</subscript> alloy processed at 773K for 300 s by ECAP were investigated. Macrotexture analysis carried out for the exit channel of ECAP shows that the basal plane of the tetragonal Nd<subscript>2</subscript>Fe<subscript>14</subscript>B crystal aligns parallel to the shear band, i.e., the c-axis texture formation normal to the shear band induced by the ECAP process. Due to this texture formation, the technical magnetization behaviour becomes anisotropic, and the remanent magnetization is clearly enhanced along the direction perpendicular to the shear band. This anisotropic microstructure is realized at a relatively low processing temperature of 773 K, well below the melting point of the Nd-rich intergranular phase. As a consequence of this lower processing temperature, the nanostructure of the melt-spun alloy remains approximately 20 to 30 nm, considerably smaller than the typical grain size obtained after conventional die-upsetting. Our study demonstrates that equal-channel angular pressing has a potential for realising anisotropic nanostructured magnets. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218979
Volume :
117
Issue :
17
Database :
Complementary Index
Journal :
Journal of Applied Physics
Publication Type :
Academic Journal
Accession number :
102606255
Full Text :
https://doi.org/10.1063/1.4918569