Rare-earth-free MnAl-C-Ni permanent magnets produced by extrusion of powder milled from bulk

Feng L, Freudenberger J, Mix T, Nielsch K, Woodcock TG (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Acta Materialia Elsevier

Book Volume: 199

Pages Range: 155-168

DOI: 10.1016/j.actamat.2020.08.031

Abstract

Rare-earth-free MnAl-C-Ni permanent magnets have been produced for the first time by extruding powders milled from bulk. The resulting materials, fabricated using different conditions, contained a large volume fraction (> 0.92) of the desired τ-phase. In terms of the maximum energy product, the best performance obtained for a whole, transverse section of the extruded material was (BH)max = 46 kJm⁻³, and was (BH)max = 49 kJm⁻³ for a sample taken from near the edge of this section. Analysis showed that this material was comparable to the long-established benchmark, comprising MnAl-C-based magnets extruded in industry from bulk or from gas-atomised powder. Such materials are no longer available. The microstructure of the materials produced here consisted of fine, recrystallised grains, which exhibited an <001> fibre texture with intermediate texture quality and of larger, non-recrystallised regions, which contained hierarchical twinning and a high density of defects. The volume fraction and size of the non-recrystallised regions was greatly reduced by decreasing the size of the initial powder particles. This led to a large increase in the squareness factor of the demagnetisation curve and consequently to the high (BH)max values observed.

Involved external institutions

Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. (IFW) / Leibniz Institute for Solid State and Materials Research Dresden

Germany (DE)

How to cite

APA:

Feng, L., Freudenberger, J., Mix, T., Nielsch, K., & Woodcock, T.G. (2020). Rare-earth-free MnAl-C-Ni permanent magnets produced by extrusion of powder milled from bulk. Acta Materialia, 199, 155-168. https://doi.org/10.1016/j.actamat.2020.08.031

MLA:

Feng, Le, et al. "Rare-earth-free MnAl-C-Ni permanent magnets produced by extrusion of powder milled from bulk." Acta Materialia 199 (2020): 155-168.

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