摘要
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.
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.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2008年第14期1669-1675,共7页
Acta Chimica Sinica
基金
中国博士后科学基金(No.20060390389)资助项目
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
TiAl intermetallic compound
oxidation property
element Nb
electronic structure
first-principle calculation
