Understanding the Effect of Oil-Based Lubricants on the Tribological Behavior of Fe–Cr Alloys from Reactive Molecular Dynamics

In this paper, the frictional behaviors of Fe-Cr alloys in the lubricating effect of oil-based lubricant are investigated through reactive molecular dynamics. It is shown that the oil-based lubricant achieves ultralow friction through hydrodynamic lubrication by linear alpha olefin (C₈H₁₆) and passivation of the friction pairs by hydrogen gas (H₂) and free H atoms generated by the friction chemistry. Moreover, there is a critical value for the transition of the crystal structure of Fe-Cr alloy from body-centered cubic (Bcc) to amorphous structure (Other), leading to a dramatic change in friction. Meanwhile, a sliding interface consisting of a large number of amorphous structures is formed near the rigid layer, which keeps the friction force stable.