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采用基于密度泛函理论的第一性原理方法研究了Zn偏析Cu晶界的原子构型和电子结构,分析了Zn偏析对Cu晶界力学性能的影响.结果表明,Zn以替换方式偏析到晶界处,Zn—Cu与Cu—Cu的成键方式类似,均为含有共价成分的金属键.Zn偏析导致少量电荷集聚于Zn与近邻Cu之间,有限地增强了晶界的结合.拉伸过程中Zn的d轨道定域性增强,Zn与近邻Cu间的电荷密度下降,削弱了Zn—Cu键,导致晶界断裂发生在Zn—Cu间.
The atomic structure and electronic structure of Zn segregated Cu grain boundaries were investigated by the first principle method based on density functional theory and the effect of Zn segregation on the mechanical properties of Cu grain boundaries was analyzed.The results show that the Zn segregates to crystallize At the junction, Zn-Cu and Cu-Cu bond in a similar way, all containing covalent metal bonds .Zn segregation causes a small amount of charge to accumulate between the Zn and the adjacent Cu, limiting the grain boundary to enhance the combination. In the process of stretching, the d orbital localization of Zn is enhanced and the charge density between Zn and neighboring Cu is decreased, which weakens the Zn-Cu bond, resulting in the occurrence of grain boundary fracture between Zn-Cu.