Enhancement of magnetic properties by controlling structures

通过控制结构增强磁性能

基本信息

批准号：
07455275
负责人：
UMEDA Takateru
金额：
$ 4.61万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455275/
关键词：
rare earth permanent magnets Nd2Fe14B rare earth magnetostrictive alloys Tb-Dy-Fe phase diagram Laves phase phase selection Tb-Dy-Fe状態図

项目摘要

This research aims to present a guide line to improve significantly magnetic properties of rare earth permanent magnets and magnetostrictive alloys by controlling solidified and heat-treated structures. For Nd-Fe-B permanent magnetic alloys, increasing of amount of Nd_2Fe_<14>B phases is necessary to enhance magnetic properties. Therefore an initial composition range is expanded to a stable phase range of primary crystallization of gamma-Fe instead of Nd_2Fe_<14>B and also prediction of metastable Nd_2Fe_<14>B is made by using a recent dendritic growth theory considered with phase selection criterion. (TbDy) Fe_2 alloy has excellent magnetostrictive properties and thus exhibits extensive applications such as being transducer and actuator materials. To achieve higher properties, it is necessary to investigate the solidification behavior, crystal growth and magnetostrictive performance of the (TbDy) Fe_2 Laves phase, and thus obtain the crystals with well controlled microstructures.1.Pha … More se selection in the Nd-Fe-B systemNear-stoichiometric Nd-Fe-B alloys were prepared with a rapid solidification method using melt-spinning technique. Crystallization of the metastable Nd_2Fe_<14>B was realized. Its relationships of to alloy composition, solidification velocity was clarified. Furthermore, the phase selection between the Nd_2Fe_<14>B and gamma-Fe was quantitatively predicted on the basis of a dendritic growth theory.2.Growth of <111>-oriented Tb-Dy-Fe single crystalMagnetostriction of the Tb-Dy-Fe alloy is highly anisotropic with the best properties along its <111> directions. However, growth of <111>-oriented single crystal was very difficult according to previous studies. In the present research, <111>-oriented Tb-Dy-Fe single crystals were grown successfully with a careful consideration on the preferred growth and twinned re-entrant stepped growth mechanism. Furthermore, the effects of alloy composition and growth conditions on the <111> growth were clarified.3.Characterization of the magnetostrictive properties of the (TbDy) Fe_2 crystalsThe magnetistrictive properties of <112>-, <110>- and <111>-oriented Tb-Dy-Fe crystals were measured. Higher properties were found in the <110> crystals than usually used <112> one. In the <111> single crystals, the largest magnetostrictive jump and the lowest saturation magnetic field in the world were obtained Less

这项研究旨在提出指南，以通过控制固化和热处理结构来改善稀土永久磁体和磁合金的显着磁性。对于ND-FE-B永久磁合金，必须增加ND_2FE_ <14> B相的量以增强磁性特性。因此，将初始组成范围扩展到伽马-FE而不是ND_2FE_ <14> B的一级结晶的稳定相位范围，并且还通过使用近期的树突状增长理论来对亚稳态ND_2FE_ <14> B进行预测。（TBDY）FE_2合金具有出色的磁性特性，因此显示出广泛的应用，例如换能器和执行材料。为了获得更高的特性，有必要研究（TBDY）FE_2 LAVES阶段的固化行为，晶体生长和磁性性能，从而获得具有良好控制的微观结构的晶体。1.PHA…在使用快速固体化方法的ND-FE-B SystemNear-Synear-Synear-Systoichiemement-Synear-Systoichiemement-Synear-systoichiemement-spoteichiement-Spoichiementric ND-FE-B Alloy中，使用融化方法准备好了。实现了亚稳态ND_2FE_ <14> B的结晶。它与合金组成，凝固速度的关系得到了阐明。此外，根据树突生长理论进行了定量预测的ND_2FE_ <14> B和Gamma-FE之间的相位选择。2.<111> <111>的增长<111>的TB-DY-FE TB-DY-FE单晶磁磁磁强度，TB-DY-FE合金的TB-DY-FE单晶磁磁图与最佳属性相对于<111> <111的最佳属性是高度的。然而，根据先前的研究，<111>面向的单晶的生长非常困难。在本研究中，成功种植了<111>面向的TB-DY-FE单晶，并仔细考虑了首选的生长和孪生的重新进入生长机制。此外，阐明了合金组成和生长条件对<111>生长的影响。3。测量（TBDY）FE_2的磁性特性的特性，测量了<112> - ，<110> - 和<111> - 和<111>> <111>的磁标准特性。在<110>晶体中发现的性质高于通常使用的<112>。在<111>单晶中，获得最大的磁性一般跳跃和世界上最低的饱和磁场的获得较少