Zr和Mo双掺杂γ-TiAl基合金的稳定性与延性预测

Predictions on the Stability and Ductility of γ-TiAl Co-doped with Zr and Mo

采用基于密度泛函理论的第一性原理方法,计算研究了Zr和Mo原子双掺杂γ-TiAl合金体系的几何结构、总能量、原子平均形成能、弹性性质、电荷密度分布和布居数。通过对形成能的计算和分析,预测各双掺杂体系均具有能量稳定性,并且Zr原子始终倾向于替代Ti原子,Mo原子的替代倾向不明显。通过对轴比、弹性模量比、电荷密度分布、电荷布居数以及重叠布居数的综合分析,发现Ti_(11)ZrAl_(11)Mo和Ti_(11)MoAl_(11)Zr体系的延性相比纯γ-TiAl体系均有较大改善,并且双掺杂体系的改善效果较单掺杂更为突出。根据弹性模量比和布居数的分析结果预测,Ti_(12)Al_(10)ZrMo可能是一种延性较好的材料。

Doped with Zr and Mo,theγ-TiAl based alloys systems were investigated by using first-principles method based on the density functional theory.The geometrical structures,total energies,average formation energies of atom,elastic properties,charge density distributions and populations were calculated and analyzed with this method.The calculation and analysis about the formation energies indicated that the doped systems possess energy stability and Zr atoms tended to substitute Ti atoms,while Mo atoms had no evident tendency.The comprehensive analysis about the axial ratios,elastic modulus ratios,charge density distributions,Mulliken populations and overlap populations predicts the ductilities of Ti 11 ZrAl 11 Mo and Ti 11 MoAl 11 Zr systems were significantly improved compared with the pureγ-TiAl system,and the effects of double doping were more pronounced than that of the single doping.The results of elastic modulus ratios and populations exhibited that Ti 12 Al 10 ZrMo system might be a kind of material with excellent ductility.