Calculation of the Electronic Structures of Advanced Intermetallic Compounds and Design for the Improvement of Ductility

先进金属间化合物电子结构的计算和延展性改进的设计

基本信息

批准号：
01550548
负责人：
MORINAGA Masahiko
金额：
$ 1.6万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550548/
关键词：
Intermetallic Compounds Mechanical Properties Electronic Structure Molecular Orbital Method

项目摘要

Electronic states of stoichiometric and non-stoichiometric TiAl compound in the course of deformation were calculated using a discrete variational (DV) CHI cluster method. For the stoichiometric TiAl the bond strength between atoms on the adjacent (111) slip planes decreased during deformation, but the decrease was relatively smaller in the [110] direction than in the [101] and [211] directions. This result indicates that the slip deformation is more active in the [110] direction than in the other two directions. The same slip system was expected to be active in the Tiーrich TiAl. However, this is no longer true for the Al-rich TiAl, where the (111), [101] slip system was found to be dominant in the Al-rich TiAl, in agreement with experiments.Alloying effects on the ductility was also investigated in this study. It was shown that the existence of directional Al p - Ti d covalent bonds causes this TiAl compound to be brittle. The addition of those elements into TiAl which weaken p-d interactions but enhance d-d interactions is most effective in improving the ductility.In addition, twin deformation was shown to be activated by substituting Cr or Mn atoms for Al atoms in TiAl.Furthermore, electronic structures of Nb_3Al and Mosi_2 were calculated, and the nature of the atomic interactions operating in these compounds was examined in detail.

使用离散变分（DV）CHI簇方法计算了化学计量和非化学计量TiAl化合物在变形过程中的电子态。对于化学计量TiAl，在变形过程中相邻（111）滑移面上的原子之间的键合强度降低，但是。 [110]方向的减小量相对小于[101]和[211]方向的减小量，这表明滑移变形在[101]和[211]方向上更加活跃。 [110] 方向比其他两个方向更活跃，但是，对于富铝 TiAl 来说，情况不再如此，其中（111），[101]。发现滑移系在富铝 TiAl 中占主导地位，与实验一致。本研究还研究了合金化对延展性的影响，结果表明定向 Al p - Ti d 共价键的存在导致了这种 TiAl 化合物。到在 TiAl 中添加这些元素会削弱 p-d 相互作用，但会增强 d-d 相互作用，这对于提高延展性最为有效。此外，通过用 Cr 或 Mn 原子替代 TiAl 中的 Al 原子，可以激活孪晶变形。计算了 Nb_3Al 和 Mosi_2 的电子结构，并详细检查了这些化合物中原子相互作用的性质。