Fundamentals of nanometric cutting of nanotwinned copper

Nanotwinned (NT) Cu containing a high density of growth twin boundaries (TBs) is one emerging precious metal for its extraordinary properties of high strength, intermediate ductility, and high electric conductivity. In the present work, we elucidate the deformation mechanisms of nanotwinned Cu subjected to the diamond cutting-based nanometric cutting by means of molecular dynamics simulations, with an emphasis on examining the influence of intrinsic microstructural parameters and extrinsic machining parameter on the nanometric cutting processes. The underlying deformation mechanisms of the materials are further correlated with the evolution of machining forces and the formation of machined surface and chips. Our simulation results indicate that dislocation slip, dislocation–TBs interactions, and TBs-associated mechanisms work in parallel in the plastic deformation of the NT Cu. In particular, dislocation–TB interactions and TBs-associated mechanisms are strongly dependent on rake angle of cutting tool, TB inclination angle, TB spacing, and grain size, which leads to strong anisotropic cutting response of NT Cu that originates from the heterogeneous localized deformation.