Molecular dynamics study on the effect of electric current on electrically-assisted scratching for crystal copper

Investigation of the effect of electric current on the plastic deformation mechanism of metals during the electrically-assisted machining process is significant in further improving surface properties. In this paper, the molecular dynamics (MD) method is adopted to simulate the electrically-assisted scratching process of crystal copper, obtaining and analyzing the surface morphology, potential energy change, von Mises stress distribution, and crystal defect structure evolution. The MD simulation results show that the electric current effectively expands the dislocation slip range, resulting in a larger plastic deformation zone. Meanwhile, the combined action of the electron wind forces and Joule heating causes more dislocations to proliferate and increases the dislocation density limit, enhancing the plastic deformation ability of the single-crystal copper. Furthermore, the electric current strengthens the dislocation-grain boundary interactions and reduces the hindering effect of the grain boundaries on dislocations, promoting more dislocations to cross the grain boundaries. This work will be helpful for guiding the optimization of surface strengthening techniques to get better surface properties of metals.