摘要
为研究纳米尺度接触过程力学行为,以刚性半球体接触压入单晶硅表面为分析对象,建立分子动力学模型并求解仿真,得到纳米尺度接触过程中微观接触区域的状态变化和接触作用力变化规律。由于粘附力作用,两表面尚未完全接触时,基体原子发生纳米尺度接触所特有的"突跳"现象。随着接触深度增加,基体原子位错和滑移带相继出现,接触区域的硅材料由初期弹性变形转向后期塑性变形。在脱离接触过程中,基体材料有部分弹性恢复,接触完全脱离时,球面仍粘附着部分硅原子。然后利用原子力显微镜,对应分子动力学模拟时的参数条件和接触过程,进行实验对比分析,实验结果表明:分子动力学模拟不但对纳米尺度接触过程力学行为的分析是可行和有效的,而且可以观察到实验无法反映的微观细节。
In order to study nanoscale contact mechanics behavior, taking the rigid hemispherical surface contacted on and pressed in the silicon surface as the research object, the molecular dynamics model of nanoscale contact process was established. State changing of microscopic contact area and variation law of contact force was acquired. Results showed that the adhesion force caused the hemispherical surface and monocrystalline silicon surface to jump-to-contact when the hemispherical surface has not fully contact with monocrystalline silicon substrate surface. With the increase of contact depth, dislocations and sliding of matrix atoms appeared successively. The initial stage of contact was mainly elastic deformation with some dislocations. The later stage of contact was plastic deformation with lots of dislocation accumulation. In the process of disengagement, the substrate material generated some extent elastic recovery. When the hemispherical surface and the matrix surface were completely out of touch, the contact surface still contacted with some matrix atoms due to adhesion phenomenon. Finally, atomic force microscopy was used to finish comparative analysis of the experiment according to the parameter conditions and the contact process of molecular dynamics. The experimental results showed that molecular dynamics simulation was practicable and effective for analysis of the nanoscale contact mechanics behavior. Moreover, molecular dynamics simulation could acquire the microscopic details that not be observed through the experiment.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2012年第11期250-255,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金资助项目(11062003)
云南省应用基础研究计划资助项目(2009ZC042M)
关键词
纳米尺度
接触
分子动力学模拟
原子力显微镜
Nanoscale, Contact, Molecular dynamics simulation, Atomic force microscopy
