中文摘要：

利用分子动力学在原子尺度模拟了单晶Cu（111）面纳构件的纳米加工过程和加工后纳构件的拉伸过程，分析了纳刻划过程的缺陷行为及加工缺陷对纳构件力学特性的影响．结果表明：在纳刻划过程中，在针尖的前方和下方形成加工变形区；当刻划深度较浅时，位错仅在表面与亚表面繁殖；随着刻划深度的增加，加工后残留的缺陷数量增加，纳构件的有序度及首次屈服应力下降：加工后的纳构件内部，尤其在针尖退出处有较高的残余应力．对加工后的纳构件施加拉伸载荷，由于存在残留加工缺陷和较高残余应力，其应力应变曲线在弹性卜升阶段有局部下降；在塑性阶段，由于位错繁殖及位错塞积和中间部分原子的迁移重构使应力应变曲线呈锯齿状逐渐下降．纳构件断裂失效前表现为单原子相连的纳链．纳构件的有序度随着刻划深度的增加而下降．在应变为0.8处，刻划较浅的纳构件的有序度较首次屈服处的有序度略好．

英文摘要：

Nanomachining and tensile process of Cu （111） plane nanostructures were simulated by molecular dynamics, and the defect behavior during nanomachining process and its effect on mechanical properties of nanostructure were analyzed at atomic scale. The results show that the atoms at the frontage or back of the AFM tip deviated from their initial positions and formed a deformation zone in nanostructure. Dislocations only propagate in surface and subsurface when scratching depth is shallow, and some dislocations formed dislocation loops as there existed stress gradient near tip. The number of residual defects increases and ordering degree of crystal structures decreases with scratching depth increasing. There existed high residual stress in subsurface, especially near the position where tool withdraw nanostructure. The tensile curves of the scratched nanostructure are not smooth, which is related to residual stress and defect at the elastic stage, and to dislocation multiplication and pile up at the plastic stage. Ordering degree of nanostructure decreases with scratching depth increasing, while ordering degree for small scratching depth at the strain of 0.8 is better than that at the first yielding of strain 0.045.