Architecture and magnetism of alnico

Lin Zhou, M. K. Miller, Ping Lu, Liqin Ke, R. Skomski, H. Dillon, Q. Xing, A. Palasyuk, Martha McCartney, David Smith, S. Constantinides, R. W. McCallum, I. E. Anderson, V. Antropov, M. J. Kramer

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

A rare-earth supply crisis has stimulated an intensive search for alternative permanent magnets. Alnico materials, alloys containing Al, Ni, Co and Fe, are functional nanostructured alloys, which show great potential for replacing the best commercial Nd-based rare-earth alloys for applications above 200 °C. However, their coercivity is ∼2-3× below theoretical limits. The coercivity of alnico depends on the nanostructure developed during spinodal decomposition. In this work, atom probe tomography, combined with advanced electron microcopy, indicate that the microstructure of alnico is sensitive to the introduction of alloying elements such as Ti and Cu, as well as the crystallographic orientation of the parent phase with respect to the direction of the imposed magnetic field during spinodal decomposition. The alnico coercivity mechanism involves interplay of size, chemistry and possibly stress at interfaces. Control of these parameters should allow reduction of the spatial dimension of the FeCo-rich precipitates and the interaction between them, which should in term increase the coercivity of alnico alloys.

Original languageEnglish (US)
Pages (from-to)224-233
Number of pages10
JournalActa Materialia
Volume74
DOIs
StatePublished - Aug 1 2014

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Magnetism
Coercive force
Spinodal decomposition
Rare earth alloys
Alloying elements
Rare earths
Permanent magnets
Tomography
Precipitates
Nanostructures
Magnetic fields
Atoms
Microstructure
Electrons

Keywords

  • Atom-probe tomography
  • Magnetic
  • Microstructure
  • Spinodal decomposition
  • TEM

ASJC Scopus subject areas

  • Ceramics and Composites
  • Metals and Alloys
  • Polymers and Plastics
  • Electronic, Optical and Magnetic Materials

Cite this

Zhou, L., Miller, M. K., Lu, P., Ke, L., Skomski, R., Dillon, H., ... Kramer, M. J. (2014). Architecture and magnetism of alnico. Acta Materialia, 74, 224-233. https://doi.org/10.1016/j.actamat.2014.04.044

Architecture and magnetism of alnico. / Zhou, Lin; Miller, M. K.; Lu, Ping; Ke, Liqin; Skomski, R.; Dillon, H.; Xing, Q.; Palasyuk, A.; McCartney, Martha; Smith, David; Constantinides, S.; McCallum, R. W.; Anderson, I. E.; Antropov, V.; Kramer, M. J.

In: Acta Materialia, Vol. 74, 01.08.2014, p. 224-233.

Research output: Contribution to journalArticle

Zhou, L, Miller, MK, Lu, P, Ke, L, Skomski, R, Dillon, H, Xing, Q, Palasyuk, A, McCartney, M, Smith, D, Constantinides, S, McCallum, RW, Anderson, IE, Antropov, V & Kramer, MJ 2014, 'Architecture and magnetism of alnico', Acta Materialia, vol. 74, pp. 224-233. https://doi.org/10.1016/j.actamat.2014.04.044
Zhou L, Miller MK, Lu P, Ke L, Skomski R, Dillon H et al. Architecture and magnetism of alnico. Acta Materialia. 2014 Aug 1;74:224-233. https://doi.org/10.1016/j.actamat.2014.04.044
Zhou, Lin ; Miller, M. K. ; Lu, Ping ; Ke, Liqin ; Skomski, R. ; Dillon, H. ; Xing, Q. ; Palasyuk, A. ; McCartney, Martha ; Smith, David ; Constantinides, S. ; McCallum, R. W. ; Anderson, I. E. ; Antropov, V. ; Kramer, M. J. / Architecture and magnetism of alnico. In: Acta Materialia. 2014 ; Vol. 74. pp. 224-233.
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