过渡元素掺杂对Mo力学性能的第一性原理研究

Mechanical properties of transition metals doped Mo:a first-principals study

基于密度泛函理论,采用第一性原理方法计算了在Mo中掺杂摩尔百分比分别为2.08%和4.17%的过渡金属元素W,Ti,Cu和Fe后,体系在[111](110)滑移系统上的广义层错能以及解理能,并研究了掺杂元素对Mo的剪切形变以及脆性一韧性的影响,研究发现,掺杂W和Ti原子会使体系剪切形变的发生变得困难,并使Mo材料变脆;而掺杂Cu和Fe原子则会使体系剪切形变的发生变得相对容易,并使Mo材料的韧性增强,此外,随着掺杂浓度的增加,掺杂W会使体系剪切形变的发生变得更为困难,并使Mo材料脆性更强;而掺杂Fe则会使体系剪切形变的发生变得更为容易,并使Mo材料的韧性更强。

For Mo doped with the transition metals W, Ti, Cu and Fe with the molar percentages of 2.08% and 4.17%, the generalized-stacking-fault energies and the cleavage energies along the direction [1ˉ11] in （110） plane are calculated by the first principles method based on the density functional theory, and the shear information and the brittle-ductile influences of the transition metals on the Mo material are investigated. It is found that doping W and Ti atoms can make the shear deformation difficult to happen and the brittleness of Mo enhanced, however, doping Cu and Fe atoms can make the shear deformation easy to happen and the ductility of Mo enhanced. Moreover, with the increase of doping concentration, the influences of W and Fe atoms are more obvious. Doping W atoms can make the shear deformation more difficult to happen and the brittleness of Mo stronger. Doping Fe atoms can make the shear deformation easier to happen and the ductility of Mo stronger.