Crystallization of Nd2Fe17Bx from stoichiometric melt composition

Gao, Jianrong; Volkmann, T.; Yang, Shaopeng; Reutzel, S.; Herlach, D.M.; Song, Xiaoping

doi:10.1016/j.jallcom.2006.06.090

Cited by 7 publications

(2 citation statements)

References 20 publications

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“…The lattice parameters of the constituent phases were obtained from the Rietveld refinements. Accordingly, the lattice parameter of alpha-Fe was found to be a=2.8701 Å, which is close to the literature value [11][12][13][14][15][16][17]. On the other hand, the lattice parameters of the Nd 2 Fe 14 B phase were calculated to be a=8.7963 Å, c=12.1923 Å and a=8.7974 Å, c=12.1509 Å for the as-received powder and the as-built sample, respectively.…”

Section: Technical Discussion Of Work Performed By All Partiessupporting

confidence: 82%

Additive Manufacturing of Near-net Shaped Permanent Magnets

Paranthaman

List

Babu

et al. 2016

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Section: Technical Discussion Of Work Performed By All Partiessupporting

confidence: 82%

Additive Manufacturing of Near-net Shaped Permanent Magnets

Paranthaman

List

Babu

et al. 2016

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“…Based on the simulation results of the solidification velocity of the melt pool in the LDED and LPBF processes shown in figures S1(b) and (e), it can be demonstrated that transformation from the primary γ-Fe phase to the primary Nd 2 Fe 14 B phase solidification does not occur in the LDED process, which is attributed to its V being below 10 −2 m s −1 . Furthermore, Gao et al [56][57][58] found that the nucleation of the Nd 2 Fe 17 B x phase becomes more favorable compared to that of the γ-Fe phase or Nd 2 Fe 14 B phase when the melt undercooling is larger than 60 K. Hence, a shift in the solidification sequence to the primary Nd 2 Fe 17 B x metastable phase from the primary γ-Fe phase can occur in the LDED Nd-Fe-B deposit. In addition, the distribution of the (Zr 0.5 Ti 0.5 )B 2 phase in the Nd 2 Fe 17 B x metastable phase matrix in figure 10(d) serves as additional evidence supporting this theory.…”

Section: Discussionmentioning

confidence: 99%

Toward understanding the microstructure characteristics, phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets

Yao,

Kang,

et al. 2023

Int. J. Extrem. Manuf.

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Nd-Fe-B permanent magnets are critical components for energy conversion and electronic devices. The key magnetic properties of Nd-Fe-B magnets, especially the coercivity and remanent magnetization, are strongly dependent on the phase characteristics and microstructure. In this work, Nd-Fe-B magnets were prepared using vacuum induction melting (VIM), laser directed energy deposition (LDED) and laser powder bed fusion (LPBF) technologies. The microstructure evolution and phase selection of Nd-Fe-B magnets were clarified in detail. The results indicated that the solidification velocity (V) and cooling rate (R) are key factors in determining the phase selection. In terms of the VIM-casting Nd-Fe-B magnet, a large volume fraction of the soft magnetic α-Fe phase (39.7 vol.%) and Nd2Fe17Bx metastable phase (34.7 vol.%) are formed due to the low R (2.3×10-1 ℃/s), while the hard magnetic Nd2Fe14B phase is only 5.15 vol.%. With increasing V (<10-2 m/s) and R (5.06×103 ℃/s), part of the soft magnetic α-Fe phase (31.7 vol.%) was suppressed, more Nd2Fe17Bx metastable phases (47.5 vol.%) were formed in the LDED-processed Nd-Fe-B magnet, and the hard magnetic Nd2Fe14B phase also had a low value (3.4 vol.%). As a result, the casting- and LDED-processed Nd-Fe-B magnets exhibit poor magnetic properties. In contrast, the high V (>10-2 m/s) and R (1.45×106 ℃/s) led to the formation of the hard magnetic Nd2Fe14B phase (55.8 vol.%) from liquid, and the α-Fe phase and Nd2Fe17Bx phase precipitation were suppressed in the LPBF-processed Nd-Fe-B magnet. Furthermore, the strong crystallographic texture on the {001} crystal plane is another reason for the remanence enhancement in the LPBF-processed Nd-Fe-B magnets. Consequently, a coercivity of 656 kA/m, a remanence of 0.79 T and maximum energy product of 71.5 kJ/m3 was achieved in the LPBF-processed Nd-Fe-B magnet, which indicated excellent magnetic performance, comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP (Nd-lean) Nd-Fe-B powder.

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Rare-Earths-Iron-Boron Compounds

Burzo

2023

Rare Earths-Transition Metals-Boron Compounds

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Crystallization of Nd2Fe17Bx from stoichiometric melt composition

Cited by 7 publications

References 20 publications

Additive Manufacturing of Near-net Shaped Permanent Magnets

Additive Manufacturing of Near-net Shaped Permanent Magnets

Toward understanding the microstructure characteristics, phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets

Rare-Earths-Iron-Boron Compounds

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