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

Bo Yao; Nan Kang; Xiangyu Li; Dou Li; Mohamed EL Mansori; Jing Chen; Haiou Yang; Hua Tan; Xin Lin

doi:10.1088/2631-7990/ad0472

International Journal of Extreme Manufacturing (Jan 2023)

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

Bo Yao,
Nan Kang,
Xiangyu Li,
Dou Li,
Mohamed EL Mansori,
Jing Chen,
Haiou Yang,
Hua Tan,
Xin Lin

Affiliations

Bo Yao: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Arts et Metiers Institute of Technology, MSMP, HESAM Université , F-51006 Châlons-en-Champagne, France; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Nan Kang: ORCiD; Arts et Metiers Institute of Technology, MSMP, HESAM Université , F-51006 Châlons-en-Champagne, France
Xiangyu Li: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Dou Li: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Mohamed EL Mansori: Arts et Metiers Institute of Technology, MSMP, HESAM Université , F-51006 Châlons-en-Champagne, France; Texas A&M Engineering Experiment Station, Institute for Manufacturing Systems , College Station, TX 77843, United States of America
Jing Chen: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Haiou Yang: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Hua Tan: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China
Xin Lin: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China; Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, MIIT China, Northwestern Polytechnical University , Xi’an, Shaanxi 710072, People’s Republic of China

DOI: https://doi.org/10.1088/2631-7990/ad0472
Journal volume & issue: Vol. 6, no. 1
p. 015002

Abstract

Read online

Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices. The essential magnetic properties of Nd-Fe-B magnets, particularly coercivity and remanent magnetization, are significantly influenced by the phase characteristics and microstructure. In this work, Nd-Fe-B magnets were manufactured 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 then clarified in detail. The results indicated that the solidification velocity ( V ) and cooling rate ( R ) are key factors in the phase selection. In terms of the VIM-casting Nd-Fe-B magnet, a large volume fraction of the α -Fe soft magnetic phase (39.7 vol.%) and Nd _2 Fe _17 B _x metastable phase (34.7 vol.%) are formed due to the low R (2.3 × 10 ^−1 °C s ^−1 ), whereas only a minor fraction of the Nd _2 Fe _14 B hard magnetic phase (5.15 vol.%) is presented. For the LDED-processed Nd-Fe-B deposit, although the Nd _2 Fe _14 B hard magnetic phase also had a low value (3.4 vol.%) as the values of V (10 ^−2 m s ^−1 ) and R (1.45 × 10 ^6 °C s ^−1 ) in the LPBF process resulted in the substantial formation of the Nd _2 Fe _14 B hard magnetic phase (55.8 vol.%) directly from the liquid, while the α -Fe soft magnetic phase and Nd _2 Fe _17 B _x metastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet. Additionally, crystallographic texture analysis reveals that the LPBF-processed Nd-Fe-B magnets exhibit isotropic magnetic characteristics. Consequently, the LPBF-processed Nd-Fe-B deposit, exhibiting a coercivity of 656 kA m ^−1 , remanence of 0.79 T and maximum energy product of 71.5 kJ m ^−3 , achieved an acceptable magnetic performance, comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP (Nd-lean) Nd-Fe-B powder.

Published in International Journal of Extreme Manufacturing

ISSN: 2631-8644 (Print); 2631-7990 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials; Technology: Technology (General): Industrial engineering. Management engineering; Science: Physics
Website: https://iopscience.iop.org/journal/2631-7990

About the journal

Abstract

Keywords