# Effect of Segregation on Deformation Behaviour of Nanoscale CoCrCuFeNi High-Entropy Alloy
## 3 Results and Discussion
### Tensile Deformation
As can be seen from Figure 7f, the bicrystal without segregation had structural defects only in the upper half of the bicrystal's cell, but the spatial arrangement of the twins did not affect the deformation mechanism, since the twins actively migrated when the crystal lattice was distorted. Figure 5: Bicrystal with chromium segregation at 12% strain. Twins are shown in red. Atoms of the disordered structure are shown in grey. The bicrystal with copper segregation at the GB broke almost along a straight line (Figure 7c). A detailed examination of the bicrystal under the strain shows that there were  
Figure 6: The tensile stress–strain curves for the considered bicrystals. The corresponding type of segregated element is indicated in the legend for each bicrystal, while the case without GB segregation is denoted as Bicrystal. The stress drop to zero corresponds to a break in the bicrystal. The considered temperature is 300 K.  
Figure 7: Bicrystals during stretching before breaking. Twins are shown in red, and atoms of the disordered structure are shown in grey. The figure shows the bicrystal with cobalt segregation (**a**), chromium segregation (**b**), copper segregation (**c**), iron segregation (**d**), and nickel segregation (**e**), and bicrystal without segregations (**f**). no amorphous bridges formed next to the crack, which suggests an increase in the plasticity of the bicrystal. The bicrystal with the chromium segregation broke in the same way; however, we can observe small amorphous bridges along the X axis close to the edge of the crack (Figure 7b). The cases of cobalt, nickel, and iron segregations were characterized by a large number of atoms of the disordered structure around the crack. Therefore, we can observe several amorphous bridges that restrained the development of the main crack (Figure 7a,d,e). The structure without segregation had a plasticity level similar to the bicrystal with nickel or cobalt segregations; however, the mechanism of deformation, in that case, was different. The segregated atoms strongly distorted the crystal lattice during the deformation, thereby contributing to the formation of amorphous bridges. In the absence of segregation, fracture resistance occurred only due to chemical bonds existing between the phases of the bicrystal (Figure 7f). The study did not reveal the specifics of the twin structure formation, which is dependent on the type of deformation, temperature, and thickness of the segregated layer. However, it is possible to gain a better understanding of this process by analyzing the deformation process with different ranges of element concentrations. These concentrations can be obtained through methods such as high cooling rates or doping. By controlling the design of HEAs, the required mechanical properties can be achieved, depending on their intended application. It is important to note that the impact of doping elements on the alloy characteristics should be studied separately, as doping can lead to the formation of various phases with reduced physical and mechanical properties.