Study of Nd-Fe-B Composite Crystal on Incommensurability

Nd-Fe-B复合晶体的不可通约性研究

• 批准号: 03680050
• 负责人: OHBA Takuya
• 金额: $ 0.96万
• 依托单位: Teikyo University, School of Science and Engineering
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03680050/
• 关键词: Nd-Fe-B; composite crystal; incommensurate; NdーFeーB

Nd-Fe-B, B-rich phase is a composite crystal which is constructed by two subsystems interpenetrating each other, i.e. Nd and Fe subsystems. Small crystals of this phase were chosen and X-ray diffraction intensities along the c axis were measured by four circle diffractometer. Relationship between the period of the structure and heat treatment was investigated. It is difficult to find the correlation between the effect of heat treatment and the period of the structure. Lattice constants of this phase were reported by several authors and they are not consistent each other, especially in c axis. In order to resolve the inconsistency, the period, c, for many samples were investigated and it is found that the period of the structure is determined by a difference of the period of Nd and Fe subsystems. The period of Nd subsystem can be easily modified but that of Fe cannot be easily modified. That is the reason why there are several reports about lattice constants. Crystal structure was investigated by some authors based on an assumption of commensurate structure. However, most of the crystal of this phase is incommensurate. For the structural study, interference effect between two subsystems, which should be considered but has not been made, was considered by using a Bessel function. Interesting results were derived through the consideration and a basic understanding of the crystal structure of the composite crystal has been revealed by this study. Precise measurements of diffraction profiles along the c axis were made with Nd and Fe absorption edges by synchrotrons radiation at Photon Factory in KEK. The periods of modulation of Nd and Fe subsystems are slightly different. It is first time to observe the contribution of Nd and Fe subsystems separately.

Nd-Fe-B，富B相是由Nd和Fe两个子系统相互穿插构成的复合晶体。选择该相的小晶体，用四圆衍射仪测量了沿c轴沿着的X射线衍射强度。研究了组织周期与热处理的关系。很难找到热处理效果与结构周期之间的相关性。这一相的晶格常数由几位作者报道，它们彼此不一致，特别是在c轴上。为了解决这一矛盾，对许多样品的周期c进行了研究，发现结构的周期是由Nd和Fe子系统的周期差决定的。Nd子系统的周期可以很容易地修改，但Fe子系统的周期不容易修改。这就是为什么有几个关于晶格常数的报告。一些作者基于公度结构的假设研究了晶体结构。然而，该相的大部分晶体是无公度的。对于结构研究，应考虑但未考虑的两个子系统之间的干扰效应通过使用贝塞尔函数来考虑。通过研究得到了一些有趣的结果，并揭示了对复合晶体结构的基本认识。在KEK的光子工厂用同步辐射对Nd和Fe的吸收边进行了沿c轴沿着的衍射轮廓的精确测量。Nd和Fe子系统的调制周期略有不同。首次观察到Nd和Fe子系统的贡献。

项目成果

T.Hara, T.Ohba, S.Miyazaki and K.Otsuka: "Electron Microscopy Study of Type II Twins in gamma_1' Cu-Al-Ni Martensite" Materials Transactions, JIM. Vol.33. 1105-1113 (1992)

T.Hara、T.Ohba、S.Miyazaki 和 K.Otsuka：“gamma_1 Cu-Al-Ni 马氏体中 II 型孪晶的电子显微镜研究”Materials Transactions，JIM。

T.Ohba,Y.Emura,K.Otsuka: "Structure Determination of the ζ_2' Martensite and the Mechanism of β_2→ζ_2' Tranoformation in a Au-49.5at%Cd Alloy" Matericls Transactions,JIM. 33. 29-37 (1992)

T.Ohba、Y.Emura、K.Otsuka：“Au-49.5at%Cd 合金中 z_2 马氏体的结构测定和 β_2→z_2 转变的机制”Materials Transactions，JIM，33. 29-37（ 1992）

M.Tobiyama, I.Endo, T.Kino, Y.Sumi, H.Uchida, N.Yamamoto, K.Yoshida, K.Watanabe, T.Ohba, K.Baba and T.Emura: "Determination of the Atomic Form Factor of Aluminum by Means of Coherent Bremsstrahlung" Physics Letter A. 166. 140-144 (1992)

M.Tobiyama、I.Endo、T.Kino、Y.Sumi、H.Uchida、N.Yamamoto、K.Yoshida、K.Watanabe、T.Ohba、K.Baba 和 T.Emura：《原子形态的测定》