Effect of grain size on the microscopic deformation microstructure of γ-Fe during nanoindentation by molecular dynamics simulation

The nanoindentation models of γ-Fe crystal with three grain sizes were established by molecular dynamics to analyze the effect of nanocrystalline grain size on the microscopic deformation microstructure of γ-Fe crystals in this paper. The calculation results show that the when the grain size is 200 nm, the number of stacking faults increases initially and then decreases, while when the grain sizes are 40 nm or 20 nm, that of stacking faults first increases and then remains basically unchanged. When the grain size is 200 nm, the maximum dislocation density is 1.29 nm−2. When the grain size is 40 nm and 20 nm, those are 2.03 nm−2 and 2.30 nm−2, respectively.