Anton Yu. Nikonov

Effect of adhesion transfer on the surface pattern regularity in nanostructuring burnishing

In the paper the influence of friction-induced adhesion of metal to the tool on the formation of surface topography under nanostructuring burnishing was studied. A comprehensive approach, including both experimental (optical microscopy and profilometry) and theoretical (computer-aided simulation) methods was used. The results showed a direct connection between values of adhesion strength of materials in contact with the workpiece surface pattern quality caused by the tool movement. Results of the experimental and theoretical study are in good agreement and allow us to identify the reason of regular profile forming during surface burnishing.

First-principles modeling of materials for nuclear energy applications

We discuss recent developments in the field of ab initio electronic structure theory and its use for studies of materials for nuclear energy applications. We review state-of-the-art simulation methods that allow for an efficient treatment of effects due to chemical and magnetic disorder, and illustrate their predictive power with examples of two materials systems, Fe-Cr-Ni alloys and Zr-Nb alloys.

Features of the microstructure development under conditions, reproducing the process of friction stir welding. Molecular-dynamics study

Friction stir welding is a recently developed technology which is used in various branches of modern engineering. The basis of this technology is the friction of the rotating cylindrical or specially shaped tool between two metal plates brought together either to meet their ends of one above another with the overlap. When applying the FSW process in various economical sectors, the important task is to study the mechanisms and identify the physical laws and factors leading to formation of structural inhomogeneities and discontinuities in the weld seam. This paper analyzes the basic mechanisms behind the structural state generation in the material subjected to severe plastic deformation and heating. To investigate the atomic mechanisms of structural changes in FSW, the modeling at atomic scale has been carried out. Results of work can be a basis for new knowledge about the microstructure evolution in FSW.

Features of the behavior of symmetrical tilt grain boundaries in BCC and FCC metals under shear loading. Molecular dynamics study

Behavior of symmetrical tilt grain boundaries under shear loading was studied in the framework of classical molecular dynamics. Grain boundaries Σ5, Σ9 and Σ11 in Ni and α-Fe were modelled. It was found that behavior of defects depends not only on the structure of boundaries, but also on the type of crystal lattice. It was shown that under external stress grain boundary behaves differently in the BCC and FCC metal. A comparison of the value of displacement of GB with the value of grain boundary slip under the condition of shear deformation was performed. These results can help to understand the features of development of plastic deformation in polycrystals under shear loading.