Molecular dynamics analysis of the effect of surface flaws of diamond tools on tool wear in nanometric cutting
Molecular dynamics analysis of the effect of surface flaws of diamond tools on tool wear in nanometric cutting
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DOI：
10.1016/j.commatsci.2017.03.006
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发表时间：
2017-06
影响因子：
3.3
通讯作者：
K. Fung;C. Tang;C. Cheung
中科院分区：
文献类型：
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作者：
K. Fung;C. Tang;C. Cheung
尽管金刚石切削工具的制造技术取得了进步，但表面缺陷或缺陷在某种程度上是不可避免的。本文利用分子动力学（MD）模拟研究了纳米切削中金刚石刀具表面的表面缺陷对刀具磨损的影响。原子脱离的统计研究结果表明，有缺陷区域的材料损失比无缺陷区域的材料损失大一个数量级。还发现平均主切削力随着缺陷深度的增加而减小，而平均推力则增加。这些响应与切割实验中的典型力信号一致。当存在表面缺陷时，循环力的波动较低，这可能与阻碍工件中剪切带的形成有关。对晶体结构的分析表明，在 MD 模拟中，碳原子簇或碳原子链从暴露的高折射率面的弱共价网络中被拉出并剥离。这些现象加速了工具的磨损，解释了缺陷对金刚石工具微观耐磨性的影响。
Despite the advances in the fabrication technologies of diamond cutting tools, surface flaws or imperfections are unavoidable to some degree. This paper investigates the effect of the surface flaws of the diamond tool surfaces on the tool wear in nanometric cutting using molecular dynamics (MD) simulation. The results of a statistical study of the detachment of atoms show that the material loss from the flawed region is one order of magnitude larger than that from the flawless region. The average principal cutting force is also found to decrease while that for the average thrust force increases with increasing depth of the flaw. These responses are in agreement with the typical force signals in cutting experiments. With the presence of a surface flaw, there is a lower fluctuation of the cyclic force that is possibly associated with the hindering of the formation of shear bands in the workpiece. An analysis of the crystal structures revealed that a cluster or a chain of carbon atoms was pulled and peeled off from these weak covalent networks of the exposed high-indexed facets in the MD simulations. These phenomena accelerate the tool wear and explain the effect of the flaws on the microscopic wear resistance of diamond tools.