| The present research work presents the multiscale modeling of nano-indentation into nickel-aluminum nano-layers using the coupled atomistics and discrete dislocation (CADD) model. In this work, the model has been extended to study the layered structures to reveal how the microscopic mechanisms lead to the observed indentation responses. Simulation results showed that the misfit dislocations at the interface played an important role to initiate the plastic deformation in the layered structures. The movements of misfit dislocations and their dissociation events from the interface were found to be affected largely by the stress field induced by the indenter. Load-displacement and hardness-displacement plots for different Ni-Al models were evaluated and their responses were compared with the behaviors of the pure metals. The hardness trends for all simulation models displayed their dependence upon simultaneous contributions from the indentation size effect (ISE) and the hardening effect. It was also observed that the atomistic consideration near the interface captured the dislocation/interface interactions more accurately compared to the continuum model. |
