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A large-scale atom simulation of nanoindentation into a thin nickel film using thequasicontinuum method was performed. The initial stages of the plasticity deformation of nickelwere studied. Several useful results were obtained as follows: (1)The response of the load versusindentation depth—on the load versus indentation depth curve, besides the straight parts cor-responding to the elastic property of nickel, the sudden drop of the load occurred several times;(2) The phenomena of dislocation nucleation—the dislocation nucleation took place when theload descended, which makes it clear that dislocation nucleation causes the drop of the load;(3)The mechanism of the dislocation emission—the Peierls-Nabarro dislocation model and a pow-erful criterion were used to analyze the dislocation emission. And the computational value was ingood agreement with the predict value; (4) The density of geometrically necessary dislocations.A simple model was used to obtain the density of geometrically necessary dislocations beneaththe indenter. Furthermore, the influence of the boundary conditions on the simulation results wasdiscussed.
A large-scale atom simulation of nanoindentation into a thin nickel film using thequasicontinuum method was performed. Several useful results were obtained as follows: (1) The response of the load versus indentation depth-on the load versus indentation depth curve, besides the straight parts cor-responding to the elastic property of nickel, the sudden drop of the load occurred several times; (2) The phenomena of dislocation nucleation-the dislocation nucleation took place when the load descended, which makes it clear that dislocation nucleation causes the drop of the load; (3) The mechanism of the dislocation emission-the Peierls-Nabarro dislocation model and a pow-erful criterion were used to analyze the dislocation emission. And the computational value was ingood agreement with the predict value; (4) The density of geometrically necessary dislocations. A simple model was used to obtain the density of precisely necessary, dislocations beneaththe indenter. furthermore, the influence of the boundary conditions on the simulation results wasdiscussed.