Molecular dynamics simulation of nanoscale machining of copper

Molecular dynamics simulations of the nanometric cutting of single-crystal copper were performed with the embedded atom method. The nature of material removal, chip formation, material defects and frictional forces were simulated. Nanometric cutting was found to comprise two steps: material removal as the tool machines the top surface, followed by relaxation of the work material to a low defect configuration, after the tool or abrasive particle has passed over the machined region. During nanometric cutting there is a local region of higher temperature and stress below the tool, for large cutting speeds. Relaxation anneals this excess energy and leads to lower dislocation work material. At high cutting speeds (180 m s−1), the machined surface is rough but the work material is dislocation free after the large excess energy has annealed the work material. At lower cutting speeds (1.8– 18 m s−1), the machined surface is smooth, with dislocations remaining in the substrate, and there is only a small excess temperature in the work material after machining. The size of the chip grows with increasing cutting speed.