Investigation of the Effect of Substrate Material in Nano-indentation Process using Molecular Dynamics Simulation

Nano-indentation is a valuable method for determining the mechanical properties of thin films. In this paper, in order to investigate the hardness of different metals, the nano-indentation process on three workpieces with nickel, copper and aluminum is studied by simulating molecular dynamics. According to the force-displacement curves, nickel and aluminum apply the most and the least force to the indenter, respectively. Based on the hardness-displacement curve obtained for the three components, aluminum has the lowest and nickel the highest hardness. The force-displacement curve of aluminum and hardness-displacement curve of nickel was validated by the force-displacement curve of aluminum and hardness-displacement of nickel in the previous study. The results of atomic phase transfer simulation showed that the deformation in nickel is mainly plastic and in aluminum elastic-plastic. Atomic accumulation was validated after the completion of the process on the copper surface with experimental results and simulation of finite element research of the past. By simulating crystal defects in workpieces, it was found that at the same depth and load, the distribution of crystal defects in aluminum, in addition to the depression area, is also present in the surface of the part and the underlying layers, while the dispersion of defects in copper and nickel is less. Dislocation motion was investigated as the main cause of slipping and deformation in workpieces.