Sm、La掺杂TiAl结构和性能的第一性原理计算

The first principle calculation for structure and mechanical property of Sm,La doping with TiAl

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Ti Al晶胞模型,运用Castep计算分析Sm、La两种稀土元素掺杂的Ti Al结构,对本征Ti Al和掺杂Ti Al的结构及力学性质进行分析.结果表明:稀土元素Sm掺入Ti Al后,Ti Al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Ti Al后,Ti Al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.

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.