Deformation behaviors and inverse Hall-Petch effect in nanoindentation of silicon: An atomistic simulation study with experimental validation

Atomistic Insights into the Phase Transformation of Single-Crystal Silicon during Nanoindentation

“…To analyze the Si substrate's response under the conical indenter, the indenter semi-angles (α) were chosen as 45°, 60°, and 70°. The Si substrate consisted of fixed, thermostat, and Newtonian layers [12,18]. The fixed layer at the bottom of the substrate was treated as a rigid body for structural stability, and the thermostat layer above the fixed layer was used to ensure reasonable outward heat conduction away from the Newtonian layer through an NVT ensemble.…”

“…MD simulations were conducted using the open source MD program Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) [24], and the atomistic configurations of the results were visualized using AtomViewer [25] and AtomEye [26]. The Si substrate consisted of fixed, thermostat, and Newtonian layers [12,18]. The fixed layer at the bottom of the substrate was treated as a rigid body for structural stability, and the thermostat layer above the fixed layer was used to ensure reasonable outward heat conduction away from the Newtonian layer through an NVT ensemble.…”

“…An atomistic analysis via molecular dynamics (MD) simulations can effectively elucidate the essential features of phase transformations, compared to the limited observations from experiments [8][9][10]. Recently, several atomistic studies on the nanoindentation of thin-film Si have been conducted by Sun et al [11], Wang et al [12], and Jiao et al [13]. However, these computational studies focused on the use of a spherical indenter.…”

The characterization of plastic behavior and mechanical properties in the gradient nanostructured copper

“…However, this event pales into insignificance when the nanoscale grains become smaller than a critical size, called the inverse Hall-Petch effect. [5][6][7][8] It is suggested that the softening effect in the nanostructured alloys with very small grain size, typically <20 nm, is associated with the change of plasticity mechanism from the dislocation-based deformation to the grain boundary (GB)-mediated deformation. 9,10 Applying ultra-severe plastic deformation, Mohammadi et al 11 fabricated an Al-based alloy with nanometer grain sizes, showing the inverse Hall-Petch mechanism.…”

“…They reported that GB segregation and precipitation are possible strategies for undoing the inverse Hall-Petch effect in this alloy. Wang et al 6 indicated the inverse Hall-Petch features in the nano-grained polycrystalline silicon under the nanoindentation process and found that the GB-induced stress is responsible for the significant formation of bct-5 silicon in the nanostructure. Jones et al 12 discovered that there is a correlation between the inverse Hall-Petch behavior of single-phase high entropy alloy (CoCrFeMnNi) and the low friction coefficient of the material.…”