权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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.

采用烧结法和快速凝固法制备了具有高磁饱和度和晶体磁各向异性的Nd2Fe；14&Gt；B稀土磁体。1988年，Shimoda et al.结果表明，Pr2Fe&lt；14&Gt；B具有热变形能力，利用磁各向异性与铸态各向异性和形变各向异性之间的关系，引入了一种新型磁体。因此，稀土磁体通过铸造、热变形和热处理等常见的金属加工路线有望得到发展。在这项研究中，我们研究了每种工艺决定的磁性和微观结构。热压过程分为三个变形阶段。在初始阶段，应力随变形的快速增加导致了试件内部的细小裂纹，导致了严重的应力松弛。在第二阶段，边界处存在液体，愈合的裂纹和晶体被重新定向到导致各向异性的流动应力方向。在最后阶段，样品被较大的变形破坏。初生Fe粒子在均热过程中消失，较低的温度下均热产生细小的组织，使其具有较高的矫顽力，在600ﾟC的热处理过程中产生能量积，使其具有较高的矫顽力。包晶反应生成的Pr_6Fe_(13)&Gt；Cu为四方反铁磁性化合物。材料设计要求考虑铁磁和反铁磁相之间的耦合。其他新的晶界相Nd(Pr)_&lt；11&gt；Fe_&lt；87&gt；B_2。