Strain Rate Effect on Indentation Behavior of Polycrystalline Sintered Silver Nanoparticles Based on Crystal Plasticity Finite Element Method

Based on crystal plasticity finite element simulation, this study explores the meso-scale mechanical behavior of polycrystalline sintered silver nanoparticles (AgNPs) under different strain rates and indentation depths using the nanoindentation method. A three-dimensional finite element indentation model of polycrystalline sintered AgNPs was constructed in ABAQUS, and the mechanical behavior of the polycrystalline sintered AgNPs was investigated under different indentation depths (500nm, 100nm, and 2000nm) and strain rates $(0.05\mathrm{s}^{-1},0.1\mathrm{s}^{-1}, \text{and}\ 0.2\mathrm{s}^{-1})$ conditions for indentation tests. As the representative parameters, the material properties, such as load-displacement curves, hardness, cumulative shear strain and the crystal orientation, were investigated. The experimental results show that the effect of indentation strain rate on the load-displacement curve is obvious, and the applied load on the indenter increases with the increase of strain rate. This underlines the strain rate effect of sintered AgNPs at the mesoscopic scale. In addition, the indentation strain rate and hardness are significantly associated in a linear relationship, indicating that the hardness is extremely sensitive to the indentation strain rate, and thus the plastic deformation behavior is significantly affected by the loading rate.