Yielding behavior of copper nanowire in the presence of vacancies  

作　　者：LIU XiaoMing YANG XiaoBin WEI YueGuang 

机构地区：[1]The State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Resources and Safety Engineering,China University of Mining&Technology,Beijing 100083,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2012年第6期1010-1017,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grants Nos. 50904071,11021262,10932011 and 91116003);the Fundamental Research Funds for the Central Universities (Grant No.2010QZ01);the National Basic Research Program of China (Grant No.2012CB937500)

摘　　要：In the present research,the measurement fluctuations of mechanical properties in nanowires (NWs) are investigated by using the molecular dynamics simulation.The large numbers of simulations are performed to study the yield behaviors of the NWs.The results have shown that the yield behavior of the smaller diameter NW is more sensitive to the presence of vacancies,and the dispersion of the measured mechanical properties for the small scale NW is larger than that for the large scale NW.Present results have also shown that vacancies escape from the bulk to the free surfaces as a result of high stress applied at the small scale systems similar to the dislocation starvation phenomenon observed in the compression test of nano-pillars,and dislocation nucleation induced by surface defect occurs after the vacancy reaches free surface leading to lower yield strength.Moreover,the strong surface vacancy interactions at the nanoscale level are also investigated.In the present research,the measurement fluctuations of mechanical properties in nanowires （NWs） are investigated by using the molecular dynamics simulation.The large numbers of simulations are performed to study the yield behaviors of the NWs.The results have shown that the yield behavior of the smaller diameter NW is more sensitive to the presence of vacancies,and the dispersion of the measured mechanical properties for the small scale NW is larger than that for the large scale NW.Present results have also shown that vacancies escape from the bulk to the free surfaces as a result of high stress applied at the small scale systems similar to the dislocation starvation phenomenon observed in the compression test of nano-pillars,and dislocation nucleation induced by surface defect occurs after the vacancy reaches free surface leading to lower yield strength.Moreover,the strong surface vacancy interactions at the nanoscale level are also investigated.

关 键 词：NANOWIRE yield strength VACANCIES size effect 

分 类 号：TG111.4[金属学及工艺—物理冶金] TB331[金属学及工艺—金属学]