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arXiv 1402.4290cond-mat.softcond-mat.other
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固体润滑剂中滑动摩擦的孤子动力学

Soliton dynamics in a solid lubricant during sliding friction

A. Vigentini, B. Van Hattem, E. Diato, P. Ponzellini, T. Meledina, A. Vanossi, G. Santoro, E. Tosatti, N. Manini

摘要:

最近的高度理想化的模型研究的润滑纳米摩擦的两个晶体滑动表面与插入薄的固体晶体润滑剂层表明,整体的相对速度的润滑剂$v_{\rm lub} / v_{\rm slider}$仅取决于晶格间距的比率,并保持严格恒定的值,即使当系统参数在很宽的范围内变化。这种奇特的“量子化”动力学锁定被理解为由于错配位错或孤子结构的滑动诱导运动。到目前为止,这一概念的实际相关性,以现实的滑动三维晶体尚未得到证明。在这项工作中,通过经典的分子动力学模拟和理论的考虑,我们实现了一个现实的三维晶体润滑剂晶体几何形状。结果表明,与前进孤子线相关联的润滑剂粒子的通量在这里也引起量子化的速度比。此外,根据界面晶格间距失配,向前和向后的量化运动的润滑剂的预测。通过改变滑动速度、温度、载荷和润滑油膜厚度,进一步研究了动态钉扎状态和量化滑动在现实条件下的持久性。文中还讨论了量子化滑动实验观测的可能性。

英文摘要:

Recent highly idealized model studies of lubricated nanofriction for two crystalline sliding surfaces with an interposed thin solid crystalline lubricant layer showed that the overall relative velocity of the lubricant $v_{\rm lub} / v_{\rm slider}$ depends only on the ratio of the lattice spacings, and retains a strictly constant value even when system parameters are varied within a wide range. This peculiar "quantized" dynamical locking was understood as due to the sliding-induced motion of misfit dislocations, or soliton structures. So far, the practical relevance of this concept to realistic sliding three dimensional crystals has not been demonstrated. In this work, by means of classical molecular dynamics simulations and theoretical considerations, we realize a realistic three-dimensional crystal-lubricant-crystal geometry. Results show that the flux of lubricant particles associated to the advancing soliton lines gives rise here too to a quantized velocity ratio. Moreover, depending on the interface lattice spacing mismatch, both forward and backward quantized motion of the lubricant is predicted. The persistence under realistic conditions of the dynamically pinned state and quantized sliding is further investigated by varying sliding speed, temperature, load, and lubricant film thickness. The possibilities of experimental observation of quantized sliding are also discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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