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

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

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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 theα-Fe soft magnetic phase(39.7 vol.％)and Nd2Fe17Bx metastable phase(34.7 vol.％)are formed due to the low R(2.3 × 10-1 ℃ s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.％)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.％)as the values of V(＜10-2 m s-1)and R(5.06 x 103 ℃ s-1)increased,part of the α-Fe soft magnetic phase(31.7 vol.％)is suppressed,and a higher volume of Nd2Fe17Bx metastable phases(47.5 vol.％)are formed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(＞10-2 m s-1)and R(1.45 × 106 ℃s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.％)directly from the liquid,while the α-Fe soft magnetic phase and Nd2Fe17Bx 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.

laser additive manufacturing(LAM)Nd-Fe-B permanent magnetsnumerical simulationmicrostructuremagnetic properties

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

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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

Texas A&M Engineering Experiment Station,Institute for Manufacturing Systems,College Station,TX 77843,United States of America

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国家重点研发计划国家自然科学基金国家自然科学基金国家留学基金委项目

2022YFB4600300U22A2018952175364202206290134

2024

10.1088/2631-7990/ad0472

极端制造(英文)

极端制造(英文)

CSTPCDEI
ISSN：
年,卷(期)：2024.6(1)