本文运用分子动力学方法模拟了单晶体Cu在微摩擦过程中的黏-滑效应。模拟结果表明：在原子尺度，摩擦表面的原子排列较规则，摩擦力曲线为大小锯齿的周期变化。这种黏-滑效应可以解释为位错机制，即摩擦表面间位错的产生与消失的过程。大小锯齿的峰值受载荷、滑动速度、接触面两侧的晶格常数及晶格位向差等多个因素的影响。载荷越大，针尖滑动时移动的原子数量越多，接触面两侧的原子排列越不规则，则小锯齿的峰值越小，并随着载荷的增大而逐渐消失。摩擦力曲线中的小锯齿峰值与滑动速度呈线性关系。不同材料的接触面和不同滑动方向的黏-滑现象并不相同。摩擦力曲线的变化周期取决于滑动过程中基体沿滑动方向的晶格常数。
The mechanisms of micro stick-slip phenomenon were investigated with the 3D Molecular Dynamics Simulations (MDS) of single-asperity dry friction on homogeneous Cu. At the atomic scale, the regular arrangement of atoms on the sliding surfaces makes a large and a small “sawtooth” displayed in the friction force curve. This can be explained by the appearance and disappearance of the dislocations on the sliding surfaces. The magnitudes of “sawtooth” depend on the load, sliding speed, and the lattice difference across the sliding surface. The higher the load, the more atoms to be moved during dry friction, and the less the magnitude of the small “sawtooth”. The magnitude of the small “sawtooth” is linear to the sliding speed. The stick-slip phenomenon varies at different sliding surfaces and different sliding directions, but the period of the “sawtooth” is just the lattice constant of the substrate along the sliding direction.
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