Effects of Geometric and Crystallographic Factors on the Reliability of Al/Si Vertically Cracked Nanofilm/Substrate Systems

Abstract

In this study, tensile tests on aluminum/silicon vertically cracked nanofilm/substrate systems were performed using atomistic simulations. Various crystallographic orientations and thicknesses of the aluminum nanofilms were considered to analyze the effects of these factors on the reliability of the nanofilm/substrate systems. The results show that systems with some specific crystallographic orientations have lower reliability compared to the other orientations because of the penetration of the vertical crack into the silicon substrate. This penetration phenomenon occurring in a specific model is related to a high coincidence of atomic matching between the interfaces in the model. This high coincidence leads to a tendency of the interface to maintain a coherent form in which the outermost silicon atoms of the substrate that are bonded to the aluminum nanofilm tend to stick with the aluminum atoms under tensile loads. This phenomenon was verified by interface energy calculations in the simulation models.

Mechanical Behaviors of Si/CNT Core/Shell Nanocomposites under Tension: A Molecular Dynamics Analysis

“…Fracture energy ( G ) for the SiNW failure was determined from the area under the tensile stress and strain curves and was calculated using the following formula [ 43 ]: where represents the critical strain for the SiNW failure, and the SI unit of G is GJ/m 3 . According to Equation (15), the G value for the pure [111]-oriented SiNW was 1.67 GJ/m 3 , whereas that for the SiNW failure in the case of Model-1 was 4.16 GJ/m 3 .…”

“…Fracture energy (G) for the SiNW failure was determined from the area under the tensile stress and strain curves and was calculated using the following formula [43]:…”

“…SiNW failure in the case of Model-1 was noticed when the tensile stress reached 44.5 GPa. Fracture energy (G) for the SiNW failure was determined from the area under the tensile stress and strain curves and was calculated using the following formula [43]:…”

Atomistic Investigation on the Blocking Phenomenon of Crack Propagation in Cu Substrate Reinforced by CNT

“…Many researchers have attempted to analyze the nonlinear behavior of nanomaterials using atomistic simulations. Recently, it was confirmed that crack penetration, contrary to the existing theory, occurred in an aluminum/silicon vertically cracked nanofilm/substrate system with a coherent interface when the system was under tension [ 8 ]. Silicon generally exhibits brittle properties, but it has been confirmed that silicon nanowires of a certain size or less cause ductile transition [ 9 ].…”

“…Until now, research on Cu/CNT composite materials has mainly focused on the performance and efficiency of devices through experimental methods, while research on mechanical reliability from a fracture mechanics perspective is insufficient. Therefore, in this study, a fracture mechanics analysis was conducted on a Cu/CNT composite specimen with a half-crack through molecular statics (MS) simulation [ 8 ]. The effect of CNT size in the composite material on the mechanical reliability of the entire composite material was analyzed, and the fracture toughness of the Cu/CNT composite material was evaluated.…”