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Mechanism of the texture development in hydrogen-disproportionation–desorption-recombination (HDDR) processed Nd–Fe–B powders

Acta Materialia

2014年12月5日(金)
(2014.12.05 更新)

Acta Materialia ( Vol85, 15 February 2015, P42–52 )
H. Sepehri-Amin, T. Ohkubo, K. Hono, K. Gȕth and O. Gutfleisch

Abstract

Microstructure evolution in Nd12.8Fe80.1B6.6Ga0.3Nb0.2 alloy powders at different hydrogen pressures during the hydrogen-disproportionation
process PH2HD  has been studied in order to understand the underlying mechanism of the texture development during the dynamic hydrogendisproportionation–
desorption-recombination (d-HDDR) process. Transmission electron microscopy showed that Fe2B grains “memorize” the
crystallographic orientation of the initial Nd2Fe14B phase and transfer it to the recombined Nd2Fe14B grains in the highly textured sample. 3-D
tomography of backscattered electron SEM images showed that recombined Nd2Fe14B grains nucleate at the interfaces of Fe2B/NdH2 phases, which
grow through the interfaces of NdH2/a-Fe phases during the DR process. Boron segregation was found at the NdH2/a-Fe interfaces, which serve as a
boron source for the growth of the recombined Nd2Fe14B grains. The mechanism of the texture development is discussed based on the microstructure
observations and the corresponding evolution of magnetic properties.
 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

その他特記事項

This work was in part supported by Japan Science Technology Agency, CREST.


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触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
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