Molecular Dynamics Study of the Development of the Dislocation Structure of an FCC Crystal Containing an Ensemble of Spherical Pores under an External Force Action

Abstract

Radiation swelling is one of the most urgent problems in radiation materials science. Its successful solution requires an understanding of the features of the mechanisms of pore healing. In this regard, there are various experimental and theoretical works devoted to this topic. At present, due to the increase in the power of computing tools, computer simulation allows for more and more complex studies and is used, among other things, in the field of materials science. In this paper, we present the results of molecular dynamics simulations devoted to the study of the processes of healing of a group of spherical pores in an fcc crystal subjected to shear deformation. As the study showed, for pores located in close proximity to each other, the formation of a common dislocation loop is characteristic, which is formed as a result of the attraction of individual loops having sections with opposite signs of helical orientation. The formation and subsequent development of such a loop contributes to a decrease in the free volume localized in the crystal in the form of pores. In addition, structural transformations that occur when a shock wave is generated in the computational cell, which creates additional stresses, are considered separately. In this case, the formation of the loop described above and the subsequent collapse of individual pores are also observed. Taking into account that the simulation was carried out at temperatures insufficient to activate diffusion processes, and the temperature control procedure was used in model experiments with wave generation, we can conclude that the shock wave is the cause of pore collapse even in the absence of high temperatures, and one of the main mechanisms of this process is the development of the dislocation structure of the ensemble of pores. Keywords: crystal, model, deformation, pore, dislocation.