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Acta Metall Sin  2017, Vol. 53 Issue (11): 1478-1486    DOI: 10.11900/0412.1961.2016.00556
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Mechanical Properties of Sintered Ce-Fe-B Magnets
Anhua LI1(), Yueming ZHANG1, Haibo FENG1, Ning ZOU2, Zhongshan Lü2, Xujie ZOU2, Wei LI1
1 Division of Functional Material, Central Iron & Steel Research Institute, Beijing 100081, China
2 Ningbo Funeng New Material Company, Ningbo 315336, China
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Anhua LI, Yueming ZHANG, Haibo FENG, Ning ZOU, Zhongshan Lü, Xujie ZOU, Wei LI. Mechanical Properties of Sintered Ce-Fe-B Magnets. Acta Metall Sin, 2017, 53(11): 1478-1486.

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Abstract  

The (R, Ce)-Fe-B magnets have been successfully industrialized in recent years. The mechanical property of sintered permanent magnets is one important aspect of their comprehensive performances, which directly influences the service reliability and the production cost. In this work, the bending strength, fracture toughness, Vickers hardness and brittleness index of commercial (R1-xCex)30.5’31.5Febal.-B1M1 (mass fraction, %) magnets with different Ce contents have been investigated. The microfractures of the magnets were observed by SEM equipped with EDS. It shows that the bending strength and the fracture toughness of (R, Ce)-Fe-B magnets have a downward tendency with increasing Ce content x, while the Vickers hardness of the magnets varies irregularly with Ce content. The optimum mechanical properties have been obtained in the (R1-xCex)30.5~31.5Febal.-B1M1 magnet with x=0.15; the bending strength, fracture toughness and brittleness index of the magnet with x=0.15 are obviously superior to those of the ordinary sintered Nd-Fe-B magnets. Some flocculent oxide phases have been discovered in the (R, Ce)-Fe-B magnet with x=0.15. The flocculent phases may absorb part of energy during crack propagating, and reduce the stress concentration at a crack tip, which is beneficial to strengthening and toughening of (R, Ce)-Fe-B magnets. However, the mechanical properties are obviously worse for the magnet with x=0.45 (Ce/ΣRE=45%). That is probably because the microstructures of the magnet with x=0.45 become deteriorated, in which abnormally large grains have been observed. The results confirm that the fracture mechanism of sintered (R, Ce)-Fe-B magnets with different Ce contents mainly appears intergranular fracture.
Key words:  sintered Ce-Fe-B magnet      mechanical property      machinable property      fracture mechanism     
Received:  13 December 2016     
ZTFLH:  TG146.4  
Fund: Supported by National Basic Research Program of China (No.2014CB643701) and National Natural Science Foundation of China (No.51331003)
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Anhua LI
Yueming ZHANG
Haibo FENG
Ning ZOU
Zhongshan Lü
Xujie ZOU
Wei LI

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https://www.ams.org.cn/EN/10.11900/0412.1961.2016.00556     OR     https://www.ams.org.cn/EN/Y2017/V53/I11/1478

Fig.1  Schematics of three-point bending test (a) and fracture toughness test (b) of the magnets(Ls—span for bending test, S—span for fracture toughness test, F—loading, unit: mm)
x Br / T Hcj / (kAm-1) Hk / (kAm-1) (BH)max / (kJm-3) Hk /Hcj ρ / (gm-3)
0* 1.27 1630 1547 313 0.95 7.538
0.15 1.32 959 940 335 0.98 7.557
0.30 1.22 1012 964 279 0.95 7.604
0.35 1.17 926 883 252 0.95 7.607
0.40 1.13 910 888 234 0.98 7.617
0.45 1.10 801 752 222 0.94 7.632
Table 1  Magnetic properties and densities of sintered (R1-xCex)30.5~31.5Febal.B1M1 magnet
Fig.2  Typical load-displacement curve of the bending tests of sintered (R, Ce)-Fe-B magnet
x Rbb / MPa KIC / (MPam1/2) Hv / MPa Hv/KIC / μm-1/2
0 321 3.66 5704 1.56
0.15 394 4.48 5606 1.25
0.3 356 3.83 5782 1.51
0.35 304 3.29 5900 1.79
0.40 306 3.56 5566 1.56
0.45 257 3.27 5753 1.76
Table 2  Mechanical properties of sintered (R1-xCex)30.5~31.5Febal.B1M1 magnets
Fig.3  Typical microfractographs of sintered (R1-xCex)30.5~31.5Febal.B1M1 magnets with x=0.15 (a), x=0.30 (b) and x=0.45 (c, d) (Fig.3d shows the local enlarged view of Fig.3c)
x Atomic fraction / %
O Fe Ce Nd Zr
0.15 65.31 32.45 2.24 - -
0.30 69.69 25.41 4.90 - -
0 28.60 66.59 - 3.72 1.09
Table 3  EDS of oxide phases in sintered (R1-xCex)30.5’31.5-Febal.B1M1 and Nd-Fe-B reference sample
Fig.4  HRSEM bending fracture image of the (R0.85Ce0.15)30.5~31.5Febal.B1M1 magnet
Fig.5  EDS spectra of oxide phases in sintered (R1-xCex)30.5’31.5Febal.B1M1 with x=0.15 (a), x=0.30 (b) and sintered Nd-Fe-B reference sample (c)
Fig.6  SEM images of microstructure (a) and fracture (b) of sintered (R0.55Ce0.45)30.5-31.5Febal.B1M1 magnet
[1] Hirosawa S, Matsuura Y, Yamamoto H, et al.Magnetization and magnetic anisotropy of R2Fe14B measured on single crystals[J]. J. Appl. Phys., 1986, 59: 873
[2] Boltich E B, Oswald E, Huang M Q, et al.Magnetic characteristics of R2Fe14B systems prepared with high purity rare earths (Ce, Pr, Dy and Er)[J]. J. Appl. Phys., 1985, 57: 4106
[3] Li D, Bogatin Y.Effect of composition on the magnetic properties of (Ce1-xNdx)13.5(Fe1-y-zCoySiz)80B6.5 sintered magnets[J]. J. Appl. Phys., 1991, 69: 5515
[4] Okada M, Sugimoto S, Ishizaka C, et al.Didymium-Fe-B sintered permanent magnets[J]. J. Appl. Phys., 1985, 57: 4146
[5] Wang J D.Preparation of sintered (Nd, RE)-Fe-B magnet by double main phase alloy method [D]. Beijing: Central Iron and Steel Research Institute, 2012(王景代. 双主相合金法制备烧结(Nd, RE)-Fe-B磁体研究 [D]. 北京: 钢铁研究总院, 2012)
[6] Herbst J F, Meyer M S, Pinkerton F E. Magnetic hardening of Ce2Fe14B [J]. J. Appl. Phys., 2012, 111: 07A718
[7] Yan C J, Guo S, Chen R J, et al.Effect of Ce on the magnetic properties and microstructure of sintered didymium-Fe-B magnets[J]. IEEE Trans. Magn., 2014, 50: 2102605
[8] Huang S L, Feng H B, Zhu M G, et al.Optimal design of sintered Ce9Nd21Febal.B1 magnets with a low-melting-point (Ce, Nd)-rich phase[J]. Int. J. Miner. Metall. Mater., 2015, 22: 417
[9] Li W, Li A H, Huang S L, et al.The study on grain-boundary microstructure of sintered (Ce, Nd)-Fe-B magnets [A], 2015 IEEE International Magnetics Conference[C]. Beijing: IEEE, 2015, 51: 2103603
[10] Pathak A K, Khan M, Gschneidner Jr K A, et al. Cerium: An unlikely replacement of dysprosium in high performance Nd-Fe-B permanent magnets[J]. Adv. Mater., 2015, 27: 2663
[11] Zhou X Q, Liu S Y, Lü X K, et al.Effects of Ce substitution amount on microstructure and properties of sintered NdFeB magnets[J]. Electr. Compon. Mater., 2013, 32(12): 25(周晓庆, 刘盛业, 吕向科等. Ce取代量对烧结NdFeB磁体微观结构和性能的影响[J]. 电子元件与材料, 2013, 32(12): 25)
[12] Zhang X F, Shi M F, Li P Z, et al.Effect of Ce addition on magnetic properties and microstructure of NdFeB based rare earth permanent magnets[J]. Chin. Rare Earths, 2013, 34(8): 12(张雪峰, 史孟飞, 李培忠等. Ce对NdFeB永磁体磁性能和微观结构的影响[J]. 稀土, 2013, 34(8): 12)
[13] Huang S L.The research of the microstructure and magnetic properties for Ce-containing magnets [D]. Beijing: Central Iron and Steel Research Institute, 2015(黄书林. 含Ce磁体微结构与磁性能的研究 [D]. 北京: 钢铁研究总院, 2015)
[14] Sun T D, Zhu J H, Wang D W.Anisotropic thermal expansion and fracture of radially oriented toroids of RE-Co permanent magnets[J]. Acta Metall. Sin., 1979, 15: 58(孙天铎, 祝景汉, 王德文. 稀土钴永磁合金的各向异性热膨胀性质及辐向取向环体的断裂) [J]. 金属学报, 1979, 15: 58).
[15] Jiang J H, Zeng Z P.Study of alloy elements affecting the fracture strength of sintered NdFeB magnets[J]. Rare Met. Mater. Eng., 1999, 28: 144(蒋建华, 曾振鹏. 合金元素对烧结NdFeB永磁材料断裂强度的影响[J]. 稀有金属材料与工程, 1999, 28: 144)
[16] Zeng Z P.A study of the fracture in sintered NdFeB permanent magnetic materials[J]. Rare Met. Mater Eng., 1996, 25(3): 18(曾振鹏. 烧结NdFeB永磁材料的断裂研究[J]. 稀有金属材料与工程, 1996, 25(3): 18)
[17] Li A H, Dong S Z, Li W.Anisotropy of mechanical properties and fracture behaviour in sintered NdFeB permanent magnetic materials[J]. Rare Met. Mater. Eng., 2003, 32: 631(李安华, 董生智, 李卫. 烧结NdFeB永磁材料的力学性能及断裂行为的各向异性[J]. 稀有金属材料与工程, 2003, 32: 631)
[18] Li A H, Dong S Z, Li W.Mechanical properties of RE permanent magnetic materials[J]. Met. Funct. Mater., 2002, 9(4): 7(李安华, 董生智, 李卫. 稀土永磁材料的力学性能[J]. 金属功能材料, 2002, 9(4): 7)
[19] Li A H, Dong S Z, Li W.Fracture in sintered Sm-Co permanent magnetic materials[J]. Sci. China, 2003, 32A: 241(李安华, 董生智, 李卫. 烧结SmCo永磁材料的断裂[J]. 中国科学, 2002, 32A: 870)
[20] Li A H, Dong S Z, Li W.A study of the anisotropy of mechanical properties and fracture behavior in sintered Sm2Co17 permanent magnetic materials[J]. Acta Phys. Sin., 2002, 51: 2320(李安华, 董生智, 李卫. 烧结Sm2Co17型永磁材料的力学性能及断裂行为的各向异性[J]. 物理学报, 2002, 51: 2320)
[21] Li A H, Li W, Dong S Z, et al.Sintered Nd-Fe-B magnets with high strength[J]. J. Magn. Magn. Mater., 2003, 265: 331
[22] Li A H, Li W, Dong S Z, et al.Effect of minor grain-boundary alloy addition on mechanical properties and microstructure of sintered Nd-Fe-B magnets[J]. Chin. J. Rare Met., 2003, 27: 531(李安华, 李卫, 董生智等. 微量添加晶界合金对烧结Nd-Fe-B力学性能及微观结构的影响[J]. 稀有金属, 2003, 27: 531)
[23] Li A H.A study on the mechanical characteristics and fracture mechanism in RE permanent magnetic materials [D]. Beijing: Central Iron & Steel Research Institute, 2003(李安华. 稀土永磁材料的力学特性及其断裂机理研究 [D]. 北京: 钢铁研究总院, 2003)
[24] Li A H, Dong S Z, Li W.Fracture in sintered Sm-Co permanent magnetic materials[J]. Sci. China, 2003, 46G: 241
[25] Li W, Li A H, Wang H J.Anisotropic fracture behavior of sintered rare-earth permanent magnets[J]. IEEE Trans. Magn., 2005, 41: 2339
[26] Wang H J, Li A H, Zhu M G, et al.Sintered Nd-Fe-B Magnets with improved impact stability[J]. J. Magn. Magn. Mater., 2006, 307: 268
[27] Wang H J, Li A H, Li W.Effect of Pr and Dy substitution on the impact resistance of sintered Nd-Fe-B magnets[J]. Intermetallics, 2006, 15: 985
[28] Li W, Li A H, Wang H J, et al. Study on strengthening and toughening of sintered rare-earth permanent magnets [J]. J. Appl. Phys., 2009, 105: 07A703
[29] Liu J F, Vora P, Walmer M H, et al. Microstructure and magnetic properties of sintered NdFeB magnets with improved impact toughness [J]. J. Appl. Phys., 2005, 97: 10H101
[30] Hu Z H.Research on the magnetic properties, temperature stability and impact toughness of sintered Nd-Fe-B magnets [D]. Shenyang: Northeastern University, 2009(胡志华. 烧结Nd-Fe-B磁体的磁性能、温度稳定性以及冲击韧性研究 [D]. 沈阳: 东北大学, 2009)
[31] Jin J Y, Zhang Y J, Ma T Y, et al.Mechanical properties of La-Ce-substituted Nd-Fe-B magnets[J]. IEEE Trans. Magn., 2016, 52: 2100804
[32] Feng C M, Wang W M, Fu Z Y.Research on machinable ceramic materials[J]. J. Wuhan Univ. Technol., 2004, 26(5): 35(冯彩梅, 王为民, 傅正义. 可加工陶瓷材料及其制造技术的研究进展[J]. 武汉理工大学学报, 2004, 26(5): 35)
[33] Hong G Y.Rare Earth Chemistry Introduction [M]. Beijing: Science Press, 2014: 46, 49, 269(洪广言. 稀土化学导论 [M]. 北京: 科学出版社, 2014: 46, 49, 269)
[34] Herbst J F, Yelon W B. Crystal and magnetic structure of Ce2Fe14B and Lu2Fe14B [J]. . Magn. Magn. Mater., 1986, 54-57: 570
[35] Rao X L, Niu E, Hu B P.Effects of cerium on permanent magnetic properties of sintered Nd-Fe-B magnets[J]. Mater. China, 2017, 36(1): 63(饶晓雷, 钮萼, 胡伯平. Ce对烧结钕铁硼磁体永磁性的影响[J]. 中国材料进展, 2017, 36(1): 63)
[36] Yan C J.Study on microstructure, properties and stability of Ce-Fe-B permanent magnetic materials [D]. Beijing: University of Chinese Academy of Sciences, 2014(严长江. Ce-Fe-B永磁材料的微观结构、性能和稳定性研究 [D]. 北京: 中国科学院大学, 2014)
[37] Alam A, Khan M, McCallum R W, et al. Site-preference and valency for rare-earth sites in (R-Ce)2Fe14B magnets[J]. Appl. Phys. Lett., 2013, 102: 042402
[38] Mo W J, Zhang L T, Liu Q Z, et al.Dependence of the crystal structure of the Nd-rich phase on oxygen content in an Nd-Fe-B sintered magnet[J]. Sci. Mater., 2008, 59: 179
[39] Zhang Y J, Ma T Y, Jin J Y, et al.Effects of REFe2 on microstructure and magnetic properties of Nd-Ce-Fe-B sintered magnets[J]. Acta Mater., 2017, 128: 22
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