Issue 49

A.V. Vakhrushev et alii, Frattura ed Integrità Strutturale, 49 (2019) 370-382; DOI: 10.3221/IGF-ESIS.49.37 378 5 b). In places where the crystal lattice changes both in the matrix and in the nanofibers, defects are formed. With an increase in the strain to 0.8 (Fig. 5 c), the area with defects fills the entire volume of the matrix and almost the entire volume of nanofibers in which failure occurs. x y z a) с) b) Figure 4 : Tension deformation of an aluminum nanocomposite with an iron nanoparticle for a simulation time of 5 psec (deformation 0.05); 20 psec (deformation 0.20) b; 45 psec (deformation 0.45). x y z a) с) b) Figure 5 : Tension deformation of an aluminum nanocomposite with an iron nanocylinder for a simulation time of 5 psec (deformation 0.05); 20 psec (deformation 0.20) b; 80 psec (deformation 0.80) c. Consider the deformation and failure of the material during the deformation of pure shear. The processes of deformation and failure of aluminum and nanocomposites with nanoparticles and iron nanofibers for cases of shear deformation are shown in Figs. 6, 7, and 8, respectively. The shift of the computational domain was carried out in the xy plane in the remaining planes the dimensional and angular parameters of the nanosystem remained unchanged. First consider the deformation and failure of pure aluminum (Fig. 6). As in the previous examples, at small shear deformations up to 0.035, the defects of the crystal structure in the sample is practically not observed (Fig. 6). In the process of deformation at this stage, the atoms have time to rearrange themselves and take a more energetically stable position. With a greater shear strain of 0.2 (Fig. 6 b), well observable straight shear bands of the crystal structure appear in the material, corresponding to plastic shear strain, often observed in experiments. With a larger shear strain of more than 0.5 (Fig. 6 c), the shear bands lose stability and lattice defects develop. Formed areas of the amorphous state of aluminum, where the crystal structure is broken. There are also local areas with a preserved crystal lattice of various orientations and orientations. The central region of the sample is subjected to the greatest restructuring of the structure and the displacement of atoms relative to the lattice sites.