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Molecular Dynamics Investigation of Tribological Phenomena in Micro Machining

微加工中摩擦现象的分子动力学研究

基本信息

批准号：
08650163
负责人：
MAEKAWA Katsuhiro
金额：
$ 1.41万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650163/
关键词：
Micro Machining Nanotribology Computer Simulation Molecular Dynamics Micro Machine Lattice Defects Dislocation Bubble Raft Model

项目摘要

The purpose of the research is to build a physical model that describes microtribological phenomena in a nano-scale material removal process. This atomistic model enables us to deal with dynamical phenomena of friction, wear and lubrication followed by elastic-plastic deformation, fracture and chemical reaction at surfaces/interfaces. The major results obtained are as follows :1.Postulating interatomic force based on the Morse potential, a (111) plane of a copper single crystal is orthogonally machined in the direction of [101]. Existing vacancies and edge dislocations in the crystal result in further disorder of the lattice structure and an increase in cutting forces. In the case of the duplex machining of the perfect crystal, displacement of the work atoms is limited to at or just below the finished surface. It is concluded that a prerequisite for a damage-free surface is that the work material should be as pure and perfect as possible. Lubrication between the tool and work atoms is a crucial factor as well.2.The bubble raft method according to Bragg and Nye has been employed to investigate the nano-scale cutting mechanisms of soap bubbles as well to make a comparison with MD simulations of a copper single crystal. Qualitative agreement can be seen with respect to basic cutting phenomena, including chip formation subsurface damage in which a similar deformation mechanism through dislocations plays a primary role. The interaction between the tool and work is also a key factor in nano-scale machining.3.The existing two-dimensional MD simulation program has successfully been extended to a three-dimensional one in which computer graphics for visualization has also been developed as application software of Windows95. Using the simulation system, more realistic tribological phenomena have been clarified, such as diffusion of the removed work atoms toward the machined surface and re-adhesion of the worn tool atoms on the tool and work surfaces.

本研究的目的是建立一个描述纳米材料去除过程中微观摩擦学现象的物理模型。这个原子模型使我们能够处理摩擦、磨损和润滑的动力学现象，然后是弹塑性变形、断裂和表面/界面的化学反应。主要结果如下：1.基于Morse势假设原子间作用力，使铜单晶的(111)晶面沿[101]方向正交加工。晶体中存在空位和刃位错导致晶格结构的进一步无序和切削力的增加。在完美晶体的双面加工中，功原子的位移被限制在加工表面或略低于加工表面的位置。得出的结论是，无损伤表面的前提是工作材料应尽可能地纯净和完美。刀具和作功原子之间的润滑也是一个关键因素。2.采用Bragg和Nye的气泡筏方法研究了肥皂泡的纳米级切割机理，并与铜单晶的分子动力学模拟进行了比较。对于基本的切割现象，包括切屑形成亚表面损伤，可以看到定性的一致，在这种损伤中，通过位错的类似变形机制起到了主要作用。刀具与工件的相互作用也是纳米加工中的一个关键因素。3.将现有的二维MD模拟程序成功地扩展到三维，并开发了可视化的计算机图形学作为Windows95的应用软件。利用该仿真系统，更真实地解释了摩擦学现象，如去除的功原子向加工表面扩散，磨损的刀具原子在刀具和工作表面重新粘着。