A metallurgical approach toward alloying in rare earth permanent magnet systems (abstract)
- Ames Laboratory, United States Department of Energy and Materials Science and Engineering Department, Iowa State University, Ames, Iowa 50011 (United States)
- Ames Laboratory, United States Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)
In bulk permanent magnets, the extrinsic properties relating to the microstructure determined the level of hard magnetic properties that is actually achieved. Many researchers have worked on the microstructure property relationships in the Nd{sub 2}Fe{sub 14}B (2-14-1) system but, in general, the approach has been to analyze the microstructure of materials which have been shown to have good magnetic properties rather than to study the effect of alloy additions on the metallurgical properties of the system. The microstructure which is obtained under a given set of processing conditions is highly dependent on the solidification behavior of the alloy, as well as grain growth phenomena. Alloy additions which effect the solidification behavior of the melt and then form precipitates which pin grain boundaries, and therefore control grain size, should be valuable in producing the uniform microstructure required for good magnetic properties. A number of refractory metal carbides perform both of these functions. The carbides have a reasonable degree of solubility in the 2-14-1 melt and, under conditions of reasonable rapid solidification, a degree of metastable solubility in the 2-14-1 phase. However, there is very limited equilibrium solid solubility in the 2-14-1 phase so that the intrinsic magnetic properties are not effected. The addition of these materials to 2-14-1 results in a factor or three reduction of the quench rate required to produce amorphous material. In addition, the crystallization temperature of the glass is enhanced leading to enhance nucleation and finer grain size during crystallization. Finally refractory metal carbide precipitates decorate the grain boundaries of the crystallized material inhibiting grain growth. Transition metal carbide formation, solid and liquid solubility, effects on solidification, nucleation, and grain growth will be discussed. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Ames National Laboratory
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 280016
- Report Number(s):
- CONF-951101-; ISSN 0021-8979; TRN: 96:018941
- Journal Information:
- Journal of Applied Physics, Vol. 79, Issue 8; Conference: 40. conference on magnetism and magnetic materials, Philadelphia, PA (United States), 6-9 Nov 1995; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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