Sm、La掺杂TiAl结构和性能的第一性原理计算

摘要

In order to research the influence of doping lanthanon on Ti-Al series ductility in room temperature, based on first⁃principles full potential linearized augmented plan wave method, we use generalized gradient approximation ( GGA) and local density approximation ( LDA) to build a unit cell model, and use Castep to calculate and analyze TiAl structure doped with Sm, La, structure and mechanical property of intrinsic TiAl and doped TiAl. The data show that as TiAl has been doped with Sm, covalency of TiAl is enhanced, bonding directivity and hardness are improved; ionicity is declined and ductility is reduced. As TiAl has been doped with La, covalency of TiAl is declined, bonding directivity and hardness are reduced;ionicity is enhanced and ductility is improved. Therefore, doping intermetallic compounds with lanthanon may improve mechanical property, it is a promising research direction.%为研究稀土元素掺杂对 Ti－Al系金属室温延性的影响，基于密度泛函理论第一性原理，应用广义梯度近似（ GGA）和局域密度近似（ LDA）平面波超软赝势法，建立稀土元素Sm、La掺杂TiAl晶胞模型，运用Castep计算分析Sm、La两种稀土元素掺杂的TiAl结构，对本征TiAl和掺杂TiAl的结构及力学性质进行分析。结果表明：稀土元素Sm掺入TiAl后，TiAl的共价性增强、成键方向性增加、硬度提高、离子性下降、延性降低；稀土元素La掺入TiAl后，TiAl的共价性下降、成键方向性减弱、硬度下降、离子性增强、延性提高。稀土元素掺杂金属间化合物，可改善其力学性能。