中国物理B ›› 2012, Vol. 21 ›› Issue (8): 87102-087102.doi: 10.1088/1674-1056/21/8/087102

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Energetics and electronic structure of refractory elements in the dislocation of NiAl

陈丽群a, 彭小方a, 于涛b   

  1. a College of Sciences, Central South University of Forestry & Technology, Changsha 410004, China;
    b Central Iron and Steel Research Institute, Beijing 100081, China
  • 收稿日期:2012-01-12 修回日期:2012-02-12 出版日期:2012-07-01 发布日期:2012-07-01
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No. 2011CB606402).

Energetics and electronic structure of refractory elements in the dislocation of NiAl

Chen Li-Qun (陈丽群)a, Peng Xiao-Fang (彭小方)a, Yu Tao (于涛)b   

  1. a College of Sciences, Central South University of Forestry & Technology, Changsha 410004, China;
    b Central Iron and Steel Research Institute, Beijing 100081, China
  • Received:2012-01-12 Revised:2012-02-12 Online:2012-07-01 Published:2012-07-01
  • Contact: Chen Li-Qun E-mail:ldclqun@163.com
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No. 2011CB606402).

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摘要： Using the DMol and the discrete variational method within the framework of density functional theory, we study the alloying effects of Nb, Ti, and V in the [100] (010) edge dislocation core of NiAl. We find that when Nb (Ti, V) is substituted for Al in the center-Al, the binding energy of the system reduces 3.00 eV (2.98 eV, 2.66 eV). When Nb (Ti, V) is substituted for Ni in the center-Ni, the binding energy of the system reduces only 0.47 eV (0.16 eV, 0.09 eV). This shows that Nb (Ti, V) exhibits a strong Al site preference, which is in agreement with experimental and other theoretical results. The analyses of the charge distribution, the interatomic energy and the partial density of states show that some charge accumulations appear between impurity atom and Ni atoms, and the strong bonding states are formed between impurity atom and neighbouring host atoms due mainly to the hybridization of 4d5s(3d4s) orbitals of impurity atom and 3d4s4p orbitals of host Ni atoms. The impurity induces a strong pinning effect on the [100] (010) edge dislocation motion in NiAl, which is related to the mechanical properties of NiAl alloy.

关键词: electronic structure, dislocation, intermetallic compounds, impurity

Abstract: Using the DMol and the discrete variational method within the framework of density functional theory, we study the alloying effects of Nb, Ti, and V in the [100] (010) edge dislocation core of NiAl. We find that when Nb (Ti, V) is substituted for Al in the center-Al, the binding energy of the system reduces 3.00 eV (2.98 eV, 2.66 eV). When Nb (Ti, V) is substituted for Ni in the center-Ni, the binding energy of the system reduces only 0.47 eV (0.16 eV, 0.09 eV). This shows that Nb (Ti, V) exhibits a strong Al site preference, which is in agreement with experimental and other theoretical results. The analyses of the charge distribution, the interatomic energy and the partial density of states show that some charge accumulations appear between impurity atom and Ni atoms, and the strong bonding states are formed between impurity atom and neighbouring host atoms due mainly to the hybridization of 4d5s(3d4s) orbitals of impurity atom and 3d4s4p orbitals of host Ni atoms. The impurity induces a strong pinning effect on the [100] (010) edge dislocation motion in NiAl, which is related to the mechanical properties of NiAl alloy.

Key words: electronic structure, dislocation, intermetallic compounds, impurity

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

  • 71.15.Mb
71.55.Ak (Metals, semimetals, and alloys) 61.72.Lk (Linear defects: dislocations, disclinations) 61.72.sh (Impurity distribution)