Aramfard Mohammad, Avanzi Luca, Nicola Lucia
Department of Industrial Engineering, University of Padova, 35131 Padua, Italy.
Tribol Lett. 2024;72(3):80. doi: 10.1007/s11249-024-01865-1. Epub 2024 Jun 24.
Atomistic simulations are performed to assess how the main characteristics of a pairwise interatomic potential function can affect the occurrence of wear. A Morse-like potential is tailored in its attractive part such as to vary independently the cut-off radius and the maximum value of the attractive (adhesive) force. An ideal numerical experiment is then performed where the interaction between a metal crystal and a probe changes, while their material properties are not affected, to isolate the behavior of the interface. Force functions with larger adhesive force can loosely be interpreted as describing dry contacts while those with smaller adhesive force can be interpreted as describing lubricated contacts. Results demonstrate that the occurrence of wear is strongly dependent on the shape of the interatomic force field, and more specifically on the combination of maximum adhesive force and effective length of the interatomic attraction. Wear can initiate also at small adhesive energy, provided that the maximum adhesive force between atoms is large. When the surface of the crystal is taken to be rough instead of flat, the effect of the interatomic potential function on friction and wear becomes smaller, as the atoms belonging to the roughness are weakly bound to the rest of the crystal and are easily dislodged with any of the force functions we used.
进行原子模拟以评估成对原子间势函数的主要特征如何影响磨损的发生。一种类莫尔斯势在其吸引部分进行了调整，以便独立改变截止半径和吸引（粘附）力的最大值。然后进行了一个理想的数值实验，其中金属晶体与探针之间的相互作用发生变化，而它们的材料特性不受影响，以分离界面的行为。具有较大粘附力的力函数大致可解释为描述干接触，而具有较小粘附力的力函数可解释为描述润滑接触。结果表明，磨损的发生强烈依赖于原子间力场的形状，更具体地说，依赖于最大粘附力和原子间吸引力有效长度的组合。只要原子间的最大粘附力较大，在较小的粘附能下也可能引发磨损。当晶体表面被视为粗糙而非光滑时，原子间势函数对摩擦和磨损的影响会变小，因为属于粗糙度的原子与晶体其余部分的结合较弱，并且在我们使用的任何力函数作用下都很容易被去除。
