Influence of the crystallographic orientation and thickness of thin copper coatings during nanoindentation

• Nanoindentation in thin copper coating by a spherical indenter.
• Influence of the crystallographic orientation and thickness of thin copper coatings.
• The crystallographic orientation influences both the elastic and plastic behavior.
• Pop-ins in the fore–displacement curve coincide with the elastic limit of the coating.
• The deformation patterns were different for different crystallographic orientations.

The structure of interest consists of a nanometer thin copper coating, resting on a stiffer substrate. The elastic and plastic properties of the coating are investigated for three crystallographic orientations and two coating thicknesses using nanoindentation simulated by molecular dynamics. The force–displacement curve, the atomic rearrangement, the stresses and the lattice disorder are monitored during indentation to determine and describe the occurrence and formation of pop-ins and pop-outs during loading. It was found that the crystallographic orientation strongly influenced both the stiffness, load for pop-in formation, the resulting deformation and the stress beneath the indenter.