High Temperature Deformation and Coercivity of R_2Fe_<14>B compound

R_2Fe_<14>B化合物的高温变形与矫顽力

基本信息

批准号：
02402046
负责人：
UMEDA Takateru
金额：
$ 22.08万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

Rare earth magnets of Nd_2Fe_<14>B that has high magnetic saturation and crystal magnetic anisotropy have been made mainly by the sintering and the rapid solidification processing. In 1988 Shimoda et al. showed that Pr_2Fe_<14>B has a hot deformability and a new type of magnetos was inroduced by utilizing the relation between the magnetic anisotropy and casting and deformation ones. Therefore rare earth magnets by a common metals processing route of casting, hot deformation and heat-treatment are expected to develop. In this research we investigated magnetic properties and micro structures determined by each processing. Hot pressing was divided into three deformation stages. At initial stage a rapid increase in stress with deformation resulted in fine cracks inside the sample that induced heavily stress relaxation. At second stage liquid existed in the boundary healed cracks and crystal grains were reoriented to the direction of flow stress that caused the anisotropy. At final stage the samples were damaged by a heavier deformation. Primary Fe particles disappeared by the soaking process and a lower temperature soaking brought about fine structures that resulted in high coercivity and energy product was formed during the annealing of 600ﾟC and its formation caused high coercivity. Pr_6Fe_<13>Cu that is formed by peritectic reaction is tetragonal and antiferromagnetic. Materials design is requested with consideration to the coupling between ferromagnetic and antiferromagnetic phases. Other new boundary phase Nd(Pr)_<11>Fe_<87>B_2.

具有高磁性满意度和晶体磁各向异性的ND_2FE_ <14> B的稀土磁铁主要是由烧结和快速固化加工制成的。 1988年，Shimoda等人。表明PR_2FE_ <14> B具有热变形性，并通过利用磁各向异性与铸造和变形之间的关系引入了一种新型的磁电机。因此，预计将通过铸造，热变形和热处理的常见金属加工途径来形成稀土磁铁。在这项研究中，我们研究了通过每个处理确定的磁性特性和微结构。热压缩分为三个变形阶段。在初始阶段，应力随着变形的速度快速增加，导致样品内部的细裂纹引起严重的应力松弛。在第二阶段，在边界愈合的裂纹中存在液体，并将晶体晶粒重新定位到引起各向异性的流动应力方向。在最后阶段，样品被较重的变形损坏。浸泡过程消失了主要的Fe颗粒，并且较低的温度浸泡会导致细胞结构，从而在600°C退火过程中形成了高矫正和能量产物，并且其形成导致高矫正性。由直体反应形成的pr_6fe_ <13> Cu是四方和抗铁磁。请求材料设计，并考虑到铁磁和抗铁磁相之间的耦合。其他新的边界阶段ND（PR）_ <11> Fe_ <87> B_2。