Molecular dynamics study on deformation and mechanics of nanoscale Au/Cu multilayers under indentation.

The effects of individual layer thickness, indentation velocity, and temperature on the mechanical properties and mechanics of nanoscale Au/Cu multilayers under indentation were studied using molecular dynamics simulations based on the many-body embedded-atom potential. The simulation results show that layer interfaces act as strong barriers that resist the propagation of dislocations, even at an extremely small individual layer thickness of 3 nm. The number of dislocations increases significantly and the growth of dislocations decreases with decreasing individual layer thickness. There is no clear relationship between the magnitude of the required indentation force and the number of film layers; however, the average required indentation force increases with increasing indentation velocity and decreasing temperature. During indentation at a relatively low velocity, dislocation propagation is more significant; the number of disordered atoms significantly increases at a relatively high indentation velocity.