Deformation Behavior of Crystalline Cr-Ni Multilayer Coatings by Using Molecular Dynamics Simulation

This work shows the atomic scale deformation behavior of crystalline multilayer coating comprising up to five Cr and Ni layers. A molecular dynamics simulation was conducted to visualize the atomic scale behavior of the multilayer during indentation/unloading and scratch. Normal and shear directional forces were recorded to compare repulsion and friction forces between the multilayer models during the indentation/unloading and scratch simulations. Dislocation lines within the layers were quantified to understand the deformation behavior of each model. Atomic scale deformation and dislocation lines after the indentation and scratch were visualized. Generation and movement of a single dislocation line during the indentation simulation were also visualized within a few picoseconds. The repulsion and friction forces of the five-layer model showed the lowest values among the models. The unloading stiffness of the five-layer model was calculated to be the lowest among the models. The amount of plastic deformation and the wear volume of the one-layer model after the indentation and scratch was calculated to be the highest among the models. The number of dislocation lines of the five-layer model showed an increasing trend during the indentation and scratch. The highest dislocation density of the five-layer model might aid in an enhancement of resistance to the plastic deformation to reduce the wear volume when scratched.