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化学学报
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化学学报 ›› 2008, Vol. 66 ›› Issue (14): 1669-1675. 上一篇    下一篇

研究论文

Nb元素影响TiAl金属间化合物键合特征的第一原理计算

吴红丽*,a 张 伟b 宫声凯a   

  1. (a北京航空航天大学材料科学与工程学院 北京 100083)
    (b利兹大学机械工程学院 英国利兹 LS2 9JT)
  • 投稿日期:2008-01-14 修回日期:2008-03-10 发布日期:2008-07-28
  • 通讯作者: 吴红丽

Effect of Nb on the Bonding Characteristics of TiAl Intermetallic Compounds: A First-principle Study

WU, Hong-Li *,a ZHANG, Wei b GONG, Sheng-Kai a   

  1. (a School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China)
    (b Mechanical Engineering, University of Leeds, LS2 9JT, UK)
  • Received:2008-01-14 Revised:2008-03-10 Published:2008-07-28
  • Contact: WU, Hong-Li

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769

被引次数

28 | 3

采用第一原理方法, 研究了Nb元素对TiAl金属间化合物电子结构及其对Ti, Al和O原子键合作用的影响. 研究结果表明, Nb元素对富Ti和富Al的TiAl金属间化合物体系电子结构及键合作用的影响不同. 对于富Ti的TiAl金属间化合物体系, Nb原子取代Ti晶格位置后, 减小了Ti费米能级处的电子密度, 削弱了Ti原子与O原子间的相互作用; 同时增强了Al原子中s电子和O原子中p电子的相互作用. 而Nb原子对富Al的TiAl金属间化合物体系中Ti/Al与O的相互作用影响较小. 同时, 向TiAl金属间化合物中掺杂Nb元素, 增大了TiO2的生成能垒, 减小了Al2O3的生成能垒, 有利于促进抗氧化膜Al2O3的生成. 因此, 添加合金化元素Nb有利于提高TiAl金属间化合物的抗氧化性能, 这与实验报道相一致.

关键词: TiAl金属间化合物, 氧化性能, Nb元素, 电子结构, 第一原理计算

First-principle calculations were performed to study the effect of Nb on the bonding characteristics of TiAl intermetallic compounds with the emphasis on the electronic interactions between Ti (Al) and O atoms. The calculation results suggest that Nb impose different influence on the electronic structure of Ti-riched and Al-riched TiAl intermetallic compounds. For the Ti-riched alloy, Nb not only reduces the electron density of Ti atom near Fermi energy level, but also enhances the interactions between Al (s) electrons and O (p) electrons. By contrast, Nb has marginal effect on the bonding characteristics of the Al-riched TiAl alloy. With the introduction of Nb, the formation energy barrier of TiO2 is increased, while the generation of anti-oxidation membrane (Al2O3) is facilitated due to the decrease of the formation energy barrier. Both aspects are beneficial to improve the oxidation resistance of the TiAl alloy, which is consistent with the experimental results.

Key words: TiAl intermetallic compound, oxidation property, element Nb, electronic structure, first-principle calculation