Simulation of the nanoindentation of hard metal carbide layer systems – the case of nanostructured ultra-hard carbide layer systems

Atomistic simulations have been performed aiming to understand the nanoindentation of transition metal carbides, the moving of atoms during such plastic deformation and to identify the structural properties which account for modifications of the hardness. Atomistic modelling permitted to simulate separately the contribution of various structural defects to the hardness of a material. It turned out that the structural features which are most decisive for hardness modifications are grain boundaries in the way of the atoms during plastic deformation. Due to the extreme interatomic forces, the plastic deformation happens not like in the well-studied cases of pure metals with their clear and obvious dislocation mechanisms. Instead, in the present case a rather collective migration of atoms on glide planes is suggested. In addition, near the indenter tip the material seems to undergo amorphization due to the high applied interatomic forces.