D. V. Bachurin

Atomistic simulation of the deformation of nanocrystalline palladium: the effect of voids

Atomistic simulations of uniaxial deformation of porous nanocrystalline palladium were performed at room temperature. The porosity was varied from 1% to 3%. The diameter of the pores was varied from 1 to 4 nm. It is found that a significant part of the void volume fraction is lost during sample preparation at high temperature. During deformation, the presence of voids does not lead to an earlier onset of dislocation activity compared to the void-free sample. Poissons ratio is found to be almost insensitive to porosity, while Youngs modulus and the stress for the initiation of grain boundary mediated plastic flow moderately decrease with increasing porosity. The total strain for the onset of plastic deformation, however, is unaffected by the porosity.

Drift of dislocation tripoles under ultrasound influence

Numerical simulations of dynamics of different stable dislocation tripoles under influence of monochromatic standing sound wave were performed. The basic conditions necessary for the drift and mutual rearrangements between dislocation structures were investigated. The dependence of the drift velocity of the dislocation tripoles as a function of the frequency and amplitude of the external influence was obtained. The results of the work can be useful in analysis of motion and self-organization of dislocation structure under ultrasound influence.

Relaxation of the residual defect structure in deformed polycrystals under ultrasonic action

Using numerical computer simulation, the behavior of disordered dislocation systems under the action of monochromatic standing sound wave has been investigated in the grain of the model two-dimensional polycrystal containing nonequilibrium grain boundaries. It has been found that the presence of grain boundaries markedly affects the behavior of dislocations. The relaxation process and changes in the level of internal stresses caused by the rearrangement of the dislocation structure due to the ultrasonic action have been studied.

Interaction of dislocation tripoles with a standing sound wave

The dynamics of the motion of various dislocation tripoles under the effect of a monochromatic standing sound wave has been studied using numerical modeling. Stable configurations of the tripoles that are in drift motion have been found and mutual transitions between these configurations have been investigated. The dependence of the velocity of drift on the frequency and the amplitude of the external effect have been obtained.