第一性原理研究Zn偏析对CuΣ5晶界的影响  

First-principles study on the effects of Zn-segregation in CuΣ5 grain boundary

作　　者：孟凡顺[1] 李久会[1] 赵星[1] 

机构地区：[1]辽宁工业大学理学院,锦州121001

出　　处：《物理学报》2014年第23期259-266,共8页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2011CB606403);辽宁省教育厅基金(批准号:L2010179)资助的课题~~

摘　　要：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 and electronic structures of a Cu grain boundary with segregated Zn have been calculated by the first-principles method based on density functional theory and the effect of Zn segregation on Cu grain boundary is also analyzed. Results show that Zn is segregated to the Cu grain boundary in the way of substitution. Both Cu and Zn have the similar bonding characteristic with their neighbors, which are metallic bonds with a little covalentlike component.The Cu grain boundary with segregated Zn has strengthened the cohesion across the boundary slightly as compared with the clean Cu grain boundary because a small amount of charge accumulation is found between Zn and near neighboring Cu atoms due to the segregation of Zn. Grain boundary with segregated Zn would be fractured between Zn and Cu atoms because the d orbit of Zn is much more localized during the tensile test, resultsing in the weakness of Zn—Cu bond.

关 键 词：第一性原理 Cu晶界 Zn偏析 拉伸测试 

分 类 号：TG111[金属学及工艺—物理冶金]