在a-C/PAO固液复合体系中引入α-烯烃（alpha-olefin, AO）分子可显著改善极端工况下的摩擦学性能，从而延长机械系统的使用寿命。然而，由于动态变载过程涉及复杂的界面应力变化和分子重排行为，使得润滑油分子与a-C界面的协同作用机制难以通过实验手段准确表征。因此，本研究利用分子动力学模拟方法，系统考察了动态变载条件下高压处理时间对a-C/PAO复合体系摩擦性能的影响规律。研究结果显示，适当的高压处理能够优化摩擦性能，其摩擦行为主要取决于吸附层稳定性和润滑油膜完整性，特别是下层吸附层的结构演变对摩擦系数起决定性作用。随着高压处理时间的增加，下层吸附层逐渐由初始易剪切的AO分子层转变为AO/PAO/碳氢分子复合层结构，致使界面剪切阻力显著增大，摩擦系数随之升高。该研究阐明了动态变载过程中固液界面结构演变与摩擦响应的内在关联，为极端工况润滑材料的设计与开发提供了理论支撑。
The incorporation of alpha-olefin (AO) molecules into the a-C/PAO solid-liquid composite system significantly enhances tribological performance under extreme conditions, thereby extending the service life of mechanical systems. However, the dynamic loading process involves complex interfacial stress variations and molecular rearrangements, making it challenging to characterize the synergistic mechanisms between lubricant molecules and the a-C interface by experimental means. Therefore, molecular dynamics simulations are employed to systematically investigate the influence of high-pressure duration on the frictional properties of the a-C/PAO system under dynamic loading. Results demonstrate that moderate high-pressure treatment optimizes friction performance, which is primarily governed by adsorption layer stability and lubricant film integrity. Notably, the structural evolution of the lower adsorption layer plays a decisive role in the friction coefficient. Prolonged high-pressure exposure transforms the initial shear-prone AO monolayer into a composite AO/PAO/hydrocarbon structure, substantially increasing interfacial shear resistance and elevating the friction coefficient. This study elucidates the intrinsic relationship between solid-liquid interfacial evolution and frictional response under dynamic loading, providing theoretical guidance for the design of advanced lubrication materials in extreme environments.

a-C/PAO固液复合体系,动态变载,界面结构演变,分子动力学模拟