Place: ICMAT 2011, Singapore
With our newly developed analysis tools we are able to directly extract dislocation lines with the corresponding line directions and the associated Burgers vectors of all dislocations inside the deformed atomistic sample. From this data, dislocation density tensors and hence geometrically necessary dislocation (GND) densities can be calculated on-the-fly based on the Nye tensor method which describes the distribution of infinitesimal dislocations. The method is applied to the large scale atomistic simulation of nanoindentation with a spherical indenter in order to investigate the lattice rotation patterns and the GND density distributions during the evolution of deformation and the results agree well with the EBSD experimental measurements in literatures. In addition, the deformation twinning is found which is accounted to the alternating rotation pattern. The presented approach provides useful insight into the deformation mechanism of nanoindentation and can extract valuable information from pure atomistic data to bridging the simulations at different length scales.