Grain boundary effects on nanoindentation of Fe bicrystal using molecular dynamic

In this study, mechanical properties of iron bicrystal with Σ5 grain boundary was calculated by molecular dynamic simulation of nanoindentation. The spherical shape indenter was used for nanoindentation. An embedded atom method interatomic potential for Fe was used for this simulation. Grain boundary effect was investigated by performing indentation simulation at different distances from the grain boundary. The effect of grain boundary on the elastic modulus, maximum shear stress and hardness of Fe bicrystal was investigated. Several load drops were detected from the obtained loading curves. These load drops are the result of the initiation of dislocation nucleation and so the transition from purely elastic to elastic-plastic deformation. The results also indicate that the maximum shear stress on the grain boundary is lower than its value far from the grain boundary. A brief dislocation reaction analysis is performed on some simulation snapshots. In addition, an algorithm was proposed and used for implementation of EAM force field on GPUs which is faster than its similar CPU codes.