Interface-governed nanometric machining behaviour of Cu/Ag bilayers using molecular dynamics simulation

The nanometric machining of Cu/Ag bilayers and pure Cu film is performed using molecular dynamics (MD) simulations.

Effects of Lubrication on the Friction in Nanometric Machining Processes: A Molecular Dynamics Approach

Physical phenomena in a nanometric machining process were studied by molecular dynamics simulations. A cylindrical tool was indented and then moved laterally on an initially flat workpiece. The focus of the study is on the effect of lubrication on the nanoscale. Therefore, the indentation and the scratching were studied both in vacuum and submersed in a lubricant. All materials were modeled by Lennard-Jones truncated and shifted potential sites. It is observed, that in the lubricated case, a substantial part of the cutting edge of the tool is in dry contact with the workpiece. Nevertheless, compared to the dry scenario, the lubrication lowers the coefficient of friction. However, the work which is needed for the indentation and the scratching is not reduced. The processed surface is found to be smoother in the lubricated case. As expected, the lubrication has an important influence on the temperature field observed in the simulation.

Choosing Appropriate Interatomic Potentials for Nanometric Molecular Dynamics (MD) Simulations

There is a need to choose appropriate interatomic empirical potentials for the molecular dynamics (MD) simulation of nanomachining, so as to represent chip formation and other cutting processes reliably. Popularly applied potentials namely; Lennard-Jones (LJ), Morse, Embedded Atom Method (EAM) and Tersoff were employed in the molecular dynamics simulation of nanometric machining of copper workpiece with diamond tool. The EAM potentials were used for the modelling of the copper-copper atom interactions. The pairs of EAM-Morse and EAM-LJ were used for the workpiece-tool (copper-diamond) atomic interface. The Tersoff potential was used for the carbon-carbon interactions in the diamond tool. Multi-pass simulations were carried out and it was observed that the EAM-LJ and the EAM-Morse pair potentials with the tool modelled as deformable with Tersoff potential were best suitable for the simulation. The former exhibit the lowest cutting forces and the latter has the lowest potential energy.

Development of Nanomachining Mechanism Based on Molecular Dynamics Simulation

Nanomachining technology has broad application prospects and molecular dynamics method is an important research tools for studying nanoscale material removal mechanism. This paper is focused on the analysis of basic principle of molecular dynamics method and the progress of nanomachining model. The nanomachining mechanism of single crystalline brittle materials and plastic materials are investigated completely, micro-nanomachining mechanism of polycrystalline material is also summarized, The challenges and future development of the nanometric machining mechanism study are also discussed.