Size effects in indentation response of thin films at the nanoscale: A molecular dynamics study

作者：Nair Arun K; Parker Edward; Gaudreau Peter; Farkas Diana^*; Kriz Ronald D

来源：International Journal of Plasticity, 2008, 24(11): 2016-2031.

DOI：10.1016/j.ijplas.2008.01.007

• Molecular dynamics
• Dislocations
• Grain boundaries
• Metallic material

The indentation response of Ni thin films of thicknesses in the nanoscale was studied using molecular dynamics simulations with embedded atom method (EAM) interatomic potentials. A series of simulations were performed in films in the [111] orientation with thicknesses varying from 4 to 12.8 nm. The study included both single crystal films and films containing low angle grain boundaries perpendicular to the film surface. The simulation results for single crystal films show that as film thickness decreases larger forces are required for similar indentation depths but the contact stress necessary to emit the first dislocation under the indenter is nearly independent of film thickness. The low angle grain boundaries can act as dislocation sources under indentation. The mechanism of preferred dislocation emission from these boundaries operates at stresses that are lower as the film thickness increases and is not active for the thinnest films tested. These results are interpreted in terms of a simple model.

• 出版日期2008-11
• 单位美国弗吉尼亚理工大学(Virginia Tech)