论文部分内容阅读
采用基于密度泛函理论(DFT)的第一性原理,研究了Ni对bcc-Fe/ε-Cu界面结合的影响。建立了ε-Cu在bcc-Fe的析出模型,选取界面两侧不同阵点位置,计算Ni在不同位置的偏聚能,分析了Ni在界面区域的占位倾向,在此基础上探究了Ni对bcc-Fe/ε-Cu界面结合的影响。利用Rice-Wang热力学模型的计算表明,当Ni原子处于偏聚能最低的位置时,能够强化界面的结合。而界面分离功计算结果显示,Ni偏聚于bcc-Fe/ε-Cu界面后,界面分离功由279.8 m J·m~(-2)增加到286.7 m J·m~(-2),表明Ni偏聚后会使界面体系更加稳定。Ni偏聚于界面后对界面区域的电子结构也产生一定影响,差分电荷密度显示,与纯bcc-Fe/ε-Cu界面相比,Ni偏聚后会在其周围聚集较多的电子,且Ni与相邻原子之间电子云方向性更为明显;同时,Ni也使近邻Cu和Fe原子的态密度(DOS)向成键态偏移,这使得Ni偏聚加强了bcc-Fe/ε-Cu界面的结合,使界面区更为稳定。
The first principle of density functional theory (DFT) was used to study the effect of Ni on the interface bonding of bcc-Fe / ε-Cu. The precipitation model of ε-Cu in bcc-Fe was established. The positions of different lattice points on both sides of the interface were selected to calculate the partial aggregation energy of Ni in different positions. The occupation tendency of Ni in the interface region was analyzed. Based on this, the Ni On bcc-Fe / ε-Cu interface binding. Calculations using the Rice-Wang thermodynamic model show that the bonding of the interface can be enhanced when the Ni atom is in the position where the partial aggregation energy is the lowest. The calculation results of the interface separation work show that the interface separation work increases from 279.8 m J · m -2 to 286.7 m J · m -2 after the segregation of Ni on the bcc-Fe / ε-Cu interface, Ni segregation will make the interface system more stable. Ni segregates at the interface and also has an influence on the electronic structure of the interface region. The difference charge density shows that when Ni is segregated, more Ni is accumulated around the interface than pure bcc-Fe / ε-Cu interface, and The directionality of the electron cloud between Ni and adjacent atoms is more obvious. At the same time, Ni also shifts the DOS of the neighboring Cu and Fe atoms to the bonding state, which makes Ni segregation strengthen bcc-Fe / ε -Cu interface combination, the interface area more stable.