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Brittleness and fracture mechanism of sintered Dy-doped NdFeB magnets

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Abstract

The brittleness and fracture behaviors of the sintered and the two-stage aged Dy-doped NdFeB magnets were studied by a unique method of acoustic emission testing and Vickers hardness indentation method in this paper. A detailed analysis on the crack propagation mechanism along the grain boundary of the main grain phase (Nd, Dy)2Fe14B was done. By comparing the acoustic emission energy count value (En) with the Vickers hardness indentation load (P), it is shown that there is a linear relationship between En and P for both the sintered and the two-stage aged Dy-doped NdFeB magnets. According to the slope of E n versus P linear lines, it can be found that the two-stage aged Dy-doped NdFeB magnet is more brittle than the sintered one. It is due to that the Nd-rich grain boundary phase of the two-stage aged Dy-doped NdFeB magnet is formed as thin film and uniformly distributes around the main grain phase, which plays a significant role in increasing the intrinsic coercive force of the magnet, but decreasing its interface binding strength. Therefore, the resistance of crack propagation along the grain boundary decreases and the brittleness increases.

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References

  1. Sagawa M, Fujimura S, Togawa N, Yamamoto H, Matsuura Y. New material for permanent magnets on a base of Nd and Fe. J Appl Phys. 1984;55(6):2083.

    Article  CAS  Google Scholar 

  2. Xie TT, Mao SD, Yu C, Wang SJ, Song ZL. Structure, corrosion, and hardness properties of Ti/Al multilayers coated on NdFeB by magnetron sputtering. Vacuum. 2012;86(10):1583.

    Article  CAS  Google Scholar 

  3. Bai G, Gao RW, Sun Y, Han GB, Wang B. Study of high-coercivity sintered NdFeB magnets. J Magn Magn Mater. 2007;308(1):20.

    Article  CAS  Google Scholar 

  4. Mo WJ, Zhang LT, Shan AD, Cao LJ, Wu JS, Komuro M. Microstructure and magnetic properties of NdFeB magnet prepared by spark plasma sintering. Intermetallics. 2007;15(11):1483.

    Article  CAS  Google Scholar 

  5. Yan M, Yu LQ, Wu JM, Cui XG. Improved magnetic properties and fracture strength of NdFeB by dehydrogenation. J Magn Magn Mater. 2006;306(2):176.

    Article  CAS  Google Scholar 

  6. Chen B, Li J, Liu Y, Wang RQ, Lian LX. Structural and magnetic properties of single-stage hot deformed NdFeB magnets prepared by different initial densities. Rare Met. 2014;33(4):448.

    Article  CAS  Google Scholar 

  7. Yu LQ, Wen YH, Yan M. Effects of Dy and Nb on the magnetic properties and corrosion resistance of sintered NdFeB. J Magn Magn Mater. 2004;283(2):353.

    Article  CAS  Google Scholar 

  8. Wang QF. Study on modification of cryogenic treatment on sintered Nd–Fe–B. Taiyuan: Taiyuan University of Science and Technology; 2010. 6.

    Google Scholar 

  9. Li AH, Li W, Dong SZ, Li XM. Sintered Nd–Fe–B magnets with high strength. J Magn Magn Mater. 2003;265(3):331.

    Article  CAS  Google Scholar 

  10. Jin L. Application research of acoustic emission induced by eddy current in metal plate crack detection. Tianjin: Hebei University of Technology; 2011. 8.

    Google Scholar 

  11. Claudio A. Utilizing acoustic emission testing to detect high-temperature hydrogen attack (HTHA) in Cr–Mo reformer reactors and piping during thermal gradients. Procedia Eng. 2011;10:3552.

    Article  Google Scholar 

  12. Li MS, Hou XR, Guo XY, Zou XW. Vickers hardness indentation method with acoustic emission to measure the brittleness of boride layer, PTCA, Part A. Phys Test. 1989;25(1):7.

    Google Scholar 

  13. Li MS, Hou XR, Cui JJ, Zhang ZZ, Liu PH. The physical nature of brittle criterion K of boride layer. Trans Met Heat Treat. 1995;16(1):43.

    Google Scholar 

  14. Woodcock TG, Zhang Y, Hrkac G, Ciuta G, Dempsey NM, Schrefl T, Gutfleisch O, Givord D. Understanding the microstructure and coercivity of high performance NdFeB-based magnets. Scr Mater. 2012;67(6):536.

    Article  CAS  Google Scholar 

  15. Vial F, Joly F, Nevalainen E, Sagawa M, Hiraga K, Park KT. Improvement of coercivity of sintered NdFeB permanent magnets by heat treatment. J Magn Magn Mater. 2002;242(2):1329.

    Article  Google Scholar 

  16. Rabinovich YM, Sergeev VV, Maystrenko AD, Kulakovsky V, Szymura S, Bala H. Physical and mechanical properties of sintered Nd–Fe–B type permanent magnets. Intermetallics. 1996;4(8):641.

    Article  CAS  Google Scholar 

  17. Jiang JH, Zeng ZP, Yu J, Wu JS, Tokunaga M. The effect of Co addition on the fracture strength of Nd–Fe–B sintered magnets. Intermetallics. 2001;9(4):269.

    Article  CAS  Google Scholar 

  18. Liu W, Wu JS. Mechanical properties and fracture mechanism study of sintered Nd–Fe–B alloy. J Alloy Compd. 2008;458(1):292.

    Article  CAS  Google Scholar 

Download references

Acknowledgments

This study was financially supported by the China National Major Special Project for the Rare Earth and Rare Metallic Materials ((2012) 1743).

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Authors and Affiliations

  1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Jinan University, Jinan, 250061, China

    Li-Na Zhao, Xiao-Li Wang & Mu-Sen Li

  2. Institute of Materials, Jiangsu University of Science and Technology, Zhenjiang, 212003, China

    Xiao-Li Wang

  3. Yantai Shougang Magnetic Materials Inc, Yantai, 265500, China

    Kai-Hong Ding, Sheng-Li Cui & Yong-Cong Sun

Authors
  1. Li-Na Zhao
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  2. Xiao-Li Wang
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  3. Kai-Hong Ding
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  4. Sheng-Li Cui
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  5. Yong-Cong Sun
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  6. Mu-Sen Li
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Correspondence to Mu-Sen Li.

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Zhao, LN., Wang, XL., Ding, KH. et al. Brittleness and fracture mechanism of sintered Dy-doped NdFeB magnets. Rare Met. 41, 2688–2692 (2022). https://doi.org/10.1007/s12598-015-0613-3

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  • DOI: https://doi.org/10.1007/s12598-015-0613-3

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