Mechanical Strengthening in Gold Thin Films: A Molecular Dynamics Analysis of Nanoindentation Effects

In recent years, there has been a growing interest in the application of nano-scale thin films in various fields such as high-density storage systems, magnetic media, and micro/nanoelectromechanical systems (MEMS/NEMS). This interest is driven by advancements in the processing of metal nanomaterials. However, in many cases, the overall performance of metal thin films is compromised by mechanical weaknesses that arise during practical use. Our research focuses on investigating the deformation mechanisms and mechanical properties of gold (Au) thin films using the nanoindentation technique and molecular dynamics simulation. Our study reveals that near the indented region, elastic behaviors are observed at lower indentation velocities. As the indentation velocity increases to 15 m/s, dislocation propagation and nucleation are initiated. Furthermore, we found that the hardness of Au is significantly dependent on the indentation velocity. The lowest hardness is observed at an indentation velocity of 5 m/s, while the highest value is attained at 15 m/s. DXA analysis demonstrates that a lower number of dislocations are generated at an indentation velocity of 5 m/s, whereas a higher quantity of dislocations is evident as the indentation velocity is increased to 15 m/s. These findings indicate that there is an increase in hardness in the Au specimen, particularly at higher indentation velocities.