CHEN Zhongmin SHI Zhengxing WANG Leyi FU Hengzhi Northwestern Polytechnical University
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Xi'an
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China
金属学报(英文版)
The hot deformation process of cast Pr_(19)Fe_(74.5)B_5Cu_(1.5) magnets were studied.It is found that the easy-axes are aligned parallel to the compressive strain direction in vari- ous hot deformation process.During hot deformation,the crushing of Pr_2Fe_(14)B matrix grains and the relative slip and rotation between the grains take place and the Pr-rich melt is squeezed out of the magnet,leading to a fine,dense and well-aligned microstruc- ture in the fully-deformed magnets.Magnetic properties of B_r=990 mT,_iH_c=880 kA/m and(BH)_m=191 kJ/m~3are obtained.The increase of coercivity is attributed to the fine Pr_2Fe_(14)B grains and the thin Pr-rich phase layer continuously distributed at the grain boundaries.The increasing remanence is resulted primarily from the develop- ment of the easy-axis alignment as well as from the densification of the Pr_2Fe_(14)B matrix. The easy-axis alignment is developed by the relative slip and rotation of the crushed Pr_2Fe_(14)B grains.A full and slow hot deformation is necessary for the good easy-axis alighnment and high magnetic properties.
关键词:
Pr-Fe-B magnet
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CHEN Zhongmin XIE Faqin SHI Zhengxing WANG Leyi FU Hengzhi Northwestern Polytechnical University
,
Xi'an
,
China
金属学报(英文版)
Characteristics of magnetic hardening in cast-hot pressed magnet Pr_(19)Fe_(74.5)B_5Cu_(1.5)were stu- died.The microstructure features and virgin magnetization curve reveal a nucleation control- led coercivity mechanism.Regression analysis shows that the intrinsic coercivity varies inversely as the logarithm of the average grain size: _iH_c(MA/m)=1.7312-0.48161nd(μm) which confirms the randomness of nucleation of reversed domains and the statistical nature of coercivity,indicating that the decrease of grain size would reduce the average number of de- fects on its surface and lower the probability of magnetization reversal of a grain and the cu- mulative fraction of the grains that have reversed their magnetization.Coercivity is thus en- hanced.
关键词:
Pr-Fe-B magnet
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陈钟敏
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史正兴
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王乐仪
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傅恒志
金属学报
研究了铸造Pr_(19)Fe_(74.5)B_5Cu_(1.5)磁体的热压变形过程,结果表明,无论经受何种变形方式,磁体易轴[001]总是沿压缩变形方向取向排列,随着热压变形的进行,磁体发生Pr_2Fe_(14)B主相晶粒的碎化和晶粒间相对滑动和转动,以及富Pr液相被挤出,最终形成细小、致密的取向组织,磁性能提高到B_r=990mT,i_H_c=880kA/m和(BH)_m=191kJ/m~3矫顽力的提高归因于主相晶粒碎化和富Pr相在晶间均匀连续分布,剩磁的提高则主要由已碎化晶粒在变形中相对滑动和转动所形成的易轴取向排列以及主相晶粒的致密化贡献,变形充分而缓慢应是获得较强易轴取向和较高磁性能的重要条件。
关键词:
Pr-Fe-B磁体
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hot deformation
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microstructure
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magnetic property
