Molecular Dynamics Simulations of High-speed Nanoscale Sliding with Third Medium

3D non-equilibrium molecular dynamics simulations are performed to investigate the friction characteristic of Fe-Fe tribopair system under third medium condition. A Fe-Fe sliding simulation model with the soft third medium (Cu nanoparticle) is built. The Friction force, evolution of the structure of interface and the temperature profiles of the sliding system are obtained. The influence of the sliding velocity to the temperature and structure change under third medium is investigated. The influence of Cu nanoparticle to the microstructure evolution and change of the friction characteristic is extremely concerned. The results show that the Cu nanoparticle can decrease the friction force and average temperature under the relatively low velocity (25m/s). However, under high velocity (150m/s), the positive effect is not obvious. A Cu nano-film would form on the surface, which is useful for weakening the destruction of the interface, and protecting the sliding blocks. Under high velocity, a mixing layer would be formed in both two cases (with or without Cu nanoparticle).