Silicene, as a silicon analogue of graphene, has attracted increasing attention due to its combination of physical and chemical properties, making it a relevant material for flexible electronics and nanotechnology. In this study, molecular dynamics simulations were used to study the effect of dislocation dipoles on the deformation behavior and mechanical properties of silicene under uniaxial tension. The wrinkle formation during tension was analyzed. Dislocation dipoles with different arm lengths were considered. A comparative analysis with graphene, the benchmark two-dimensional material, was also performed. The results showed that the strength of silicene smoothly decreases with increasing defect size. In contrast, graphene exhibits a sharp drop in strength when a critical defect size is reached; thereafter, further increases in the defect size have little effect on its mechanical properties. At the same time, the fracture strain of both materials depends only weakly on defects due to their ability to form wrinkles, which redistribute stress throughout the structure. The simulation results revealed differences in the wrinkle morphology of graphene and silicene, which are determined by their atomic structures. The planar structure of graphene forms uniform one-dimensional ripples, whereas the buckled structure of silicene leads to the formation of inhomogeneous wrinklons. Unlike graphene, with transition from a flat to a wrinkled state and from a wrinkled to a flat state again during deformation, the wrinkles in silicene persist until failure. These results are important for studying the strength and defect influence in two-dimensional materials, as well as for assessing their potential applications in flexible electronics.
Using the molecular dynamics method, a study of the compression deformation of nickel nanoparticles with amorphous and nanocrystalline structures at low temperatures was conducted. The influence of the size of nanoparticles on their strength and on the strain value at which maximum stress is reached has been investigated. The characteristics of deformation behavior in the case of amorphous and nanocrystalline nanoparticles were identified. It was shown that as the size of the nanoparticles decreased, both for amorphous and nanocrystalline types, their strength increased. The strength values for nanocrystalline nickel particles were approximately twice as high as those for particles with an amorphous structure. With decreasing particle size, the strain value at which maximum stress was reached during compression of the nanoparticles also increased. One possible reason for the influence of particle size on its strength in the case of an amorphous structure may be densification and partial crystallization of the structure near the load application sites. Partial crystallization in the contact patch regions during compression of amorphous nanoparticles was observed in the model in most cases. During compression of particles with a nanocrystalline structure, frequent phenomena included grain rotation and grain boundary sliding. As with amorphous nanoparticles, the phenomenon of structural densification near the contact patches and its reorientation were observed, such that the most densely packed atomic planes of the (111) type became parallel to the contact patch plane.