MOLECULAR DYNAMICS SIMULATION OF NANOMACHINING PROCESS AND MECHANICAL PROPERTIES OF NANOSTRUCTURE
MOLECULAR DYNAMICS SIMULATION OF NANOMACHINING PROCESS AND MECHANICAL PROPERTIES OF NANOSTRUCTURE
复制标题
纳米加工过程和纳米结构力学性能的分子动力学模拟
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
陈家轩
中科院分区：
文献类型：
--
作者：
梁迎春;白清顺;陈明君;唐玉兰;陈家轩
用分子动力学方法模拟了Cu（111）平面纳米结构的纳米加工和拉伸过程，结果表明，在原子尺度下，AFM针尖前端或后端的原子偏离初始位置，在纳米结构中形成形变区，位错只在表面和亚表面传播，而在原子尺度下，位错只在表面和亚表面传播。划痕深度较浅，由于尖端附近存在应力梯度，部分位错形成位错环;随着划痕深度的增加，残余缺陷数量增加，晶体结构有序度降低;亚表面存在较高的残余应力，尤其是在刀具退出纳米结构的位置附近;划痕后纳米结构的拉伸曲线不光滑，随着划痕深度的增加，纳米结构的有序度降低，小划痕深度下0.8应变下的有序度优于0.045应变下的有序度。
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.