Ce浓度对TiAl金属间化合物结构和性能的影响

The influence of the doping concentration of rare earth Ce on the structure and performance of TiAl intermetallic compound

用第一性原理的方法,利用Castep计算模块,建立TiAl晶胞模型和不同Ce浓度掺杂TiAl 2×2×2超晶胞模型,对模型进行优化后计算其电子结构、弹性及电子性质,以期从本质上揭示稀土元素Ce掺杂浓度对TiAl结构和性能的影响,为提高TiAl性能提供理论基础。计算结果表明,稀土元素Ce掺入使TiAl内部轨道杂化作用增强,共价性增强,成键方向性增加,硬度提高。Ce原子与Ti、Al原子之间成离子键,离子性增强,延性提高。随着Ce掺杂浓度的提高,TiAl延性和硬度均有所提高。

The method of first principle was adopted to establish TiAl crystal cell model and the supercell model of different concentrations of Ce doping TiAl 2×2×2,LaTiAl 2×2×2by using Castep calculation module.The electronic structure,elasticity and electronic properties were calculated after optimization of the model to reveal the influence of rare earth element Ce doping concentration on the structure and performance of TiAi,which provides the oretical foundation for improving the performance of TiAl.The calculation results showed that the incorporation of rare earth element Ce made TiAl internal orbital hybridization enhanced,the covalent increased,the bonding directionality increased,the hardness improved.Ionic bond formed between Ce and Ti,Al atoms so it made the ionicity increased and the ductile improved.Along with the increase of the concentration of the Ce doping,the ductility and hardness of TiAl are increased.