中国物理B ›› 2006, Vol. 15 ›› Issue (3): 604-609.doi: 10.1088/1009-1963/15/3/027

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Effect of element Re on the grain boundary cohesion of α-Fe

陈征征1, 王崇愚2   

  1. (1)Department of Physics, Tsinghua University, Beijing 100084, China; (2)Department of Physics, Tsinghua University, Beijing 100084, China;China Center of Advanced Science and Technology (World Laboratory, Beijing 100080,China
  • 收稿日期:2005-07-14 修回日期:2005-09-02 出版日期:2006-03-20 发布日期:2006-03-20
  • 基金资助:
    Project supported by the State Key Development Program for Basic Research of China (Grant No G2000067102).

Effect of element Re on the grain boundary cohesion of $\alpha$-Fe

Chen Zheng-Zheng (陈征征)a, Wang Chong-Yu (王崇愚)ab   

  1. a Department of Physics, Tsinghua University, Beijing 100084, China; b China Center of Advanced Science and Technology (World Laboratory, Beijing 100080,China
  • Received:2005-07-14 Revised:2005-09-02 Online:2006-03-20 Published:2006-03-20
  • Supported by:
    Project supported by the State Key Development Program for Basic Research of China (Grant No G2000067102).

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摘要： The effect of Re segregation on the $\alpha $-Fe $\Sigma $5 [001] (010) grain boundary (GB) is investigated by using a software called DMol and discrete variational method (DVM). Based on the Rice--Wang model, the calculated segregation energy and defect formation energy show that Re is a strong cohesive enhancer. We also calculated the interatomic energy (IE) and bond order (BO) of several atomic pairs to investigate the mechanism of the cohesive effect of Re microscopically and locally. The results show that IEs of atomic pairs formed by those atoms which cross the plane of GB are strengthened due to the segregation of Re, while the BOs of the corresponding pairs are slightly decreased. This discrepancy demonstrates that IE which contains the Hamiltonian of interaction between atoms is a good quantity to describe the bonding strength. The analysis suggests that the electronic effect between atomic pair which comes directly from Hamiltonian is the key factor. The charge density is also presented, and the result indicates that the bonding strength between the Fe atoms on the GB is enhanced due to the segregation of Re, which is consistent with the analysis of IE.

关键词: mechanical properties, grain boundary, first-principles electron theory

Abstract: The effect of Re segregation on the $\alpha $-Fe $\Sigma $5 [001] (010) grain boundary (GB) is investigated by using a software called DMol and discrete variational method (DVM). Based on the Rice--Wang model, the calculated segregation energy and defect formation energy show that Re is a strong cohesive enhancer. We also calculated the interatomic energy (IE) and bond order (BO) of several atomic pairs to investigate the mechanism of the cohesive effect of Re microscopically and locally. The results show that IEs of atomic pairs formed by those atoms which cross the plane of GB are strengthened due to the segregation of Re, while the BOs of the corresponding pairs are slightly decreased. This discrepancy demonstrates that IE which contains the Hamiltonian of interaction between atoms is a good quantity to describe the bonding strength. The analysis suggests that the electronic effect between atomic pair which comes directly from Hamiltonian is the key factor. The charge density is also presented, and the result indicates that the bonding strength between the Fe atoms on the GB is enhanced due to the segregation of Re, which is consistent with the analysis of IE.

Key words: mechanical properties, grain boundary, first-principles electron theory

中图分类号:  (Grain and twin boundaries)

  • 61.72.Mm
64.75.-g (Phase equilibria) 71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 71.20.-b (Electron density of states and band structure of crystalline solids) 61.50.Lt (Crystal binding; cohesive energy)