Yin Zhiyuan, Wu Hong, Zhang Guangan, Mu Chenzhong, Bai Lichun
Key Laboratory of Traffic Safety on Track, Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha 410075, China.
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
Materials (Basel). 2022 Jan 25;15(3):893. doi: 10.3390/ma15030893.
This study employs the energy-dissipation method to analyze the tribological behaviors of diamond-like carbon (DLC) films through molecular dynamics simulation. It is found that at small load and sliding velocity, the variation trend of average friction force is only dependent on the number of interface bonds (or contact area). However, at large load and sliding velocity, the friction mechanism is not only related to the number of interface bonds but also related to the presence of the transfer layer. The elastic-plastic deformation mainly occurs in the early sliding stage, and a part of the stored elastic potential energy is dissipated by plastic potential energy or internal frictional heat. After the sliding stabilization, over 95% of the total frictional energy is dissipated by thermal conduction, and the rest is mostly dissipated by wear. The increase in load, velocity, and temperature cause more frictional energy dissipated by elastic-plastic deformation, atomic motion, and elastic deformation instead of thermal conduction, respectively. Finally, the wear rate obtained in this work is the same order of magnitude as the experiment. Generally, this work provides an effective atomic-scale method to comprehensively analyze the microscopic wear mechanism of materials.
本研究采用能量耗散方法，通过分子动力学模拟分析类金刚石碳（DLC）薄膜的摩擦学行为。研究发现，在小载荷和滑动速度下，平均摩擦力的变化趋势仅取决于界面键的数量（或接触面积）。然而，在大载荷和滑动速度下，摩擦机制不仅与界面键的数量有关，还与转移层的存在有关。弹塑性变形主要发生在滑动初期，一部分储存的弹性势能通过塑性势能或内摩擦热耗散。滑动稳定后，总摩擦能量的95%以上通过热传导耗散，其余大部分通过磨损耗散。载荷、速度和温度的增加分别导致更多的摩擦能量通过弹塑性变形、原子运动和弹性变形而不是热传导耗散。最后，本工作获得的磨损率与实验结果处于同一数量级。总体而言，本工作提供了一种有效的原子尺度方法，用于全面分析材料的微观磨损机制。
