Atomistic Simulations of the Incipient Plastic Deformation Mechanisms on Metal Surfaces.

We know since decades that, to exploit and control mechanical properties of materials, a profound knowledge of the defects generated during deformation is required. The advent of nanotechnologies and the maturity of surface science have catalysed the development of nanoindentation techniques. Nanoindentation experiments, with both high spatial and load resolution, allow to determine defects emerging at the surface, and their relationship with discontinuities in the load vs. penetration curve. But sub-surface defect morphology generally remains hidden, and quite often only indirect conclusions can be inferred. Simulations are then a very valuable tool to unveil defect configurations. Among the present challenges regarding nanoindentation, one is the origin and correct interpretation of the piled-up material, i.e. the material displaced from the indentation point. Another problem is the role of the surface roughness on the mechanical properties at the nanoscale. [ABSTRACT FROM AUTHOR]