Possibility of a vortex mechanism of displacement of the grain boundaries under high-rate shear loading

Псахье, С. Г.; Zolnikov, Konstantin

doi:10.1007/bf02672735

Cited by 28 publications

(5 citation statements)

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“…Note that elastic vortex related mechanism of stress redistribution in solids determines not only the regularities of dynamic crack growth (including sub-Rayleigh-to-supershear transition [7]) but peculiarities of deformation of materials under dynamic loading as well [8]. For example recent results of numerical modeling demonstrate that the vortex related mechanism can be responsible for grain boundary migration and "hot spots" formation under highrate shear loading [9,10] as well as for the formation of mechanically mixed layers in tribological systems [11].…”

Section: Resultsmentioning

confidence: 99%

Parametric study of the conditions of supershear crack propagation in brittle materials

Shilko

Psakhie

Popov

2015

AIP Conference Proceedings

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The paper is devoted to the numerical analysis of the conditions of acceleration of dynamically propagating longitudinal shear cracks from sub-Rayleigh to intersonic/supershear velocities. We showed that an ability of the initial crack to propagate in supershear regime can be predicted with use of the empirically derived dependence of the geometrical criterion of sub-Raleigh-to-intersonic transition on material and crack parameters.

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Section: Resultsmentioning

confidence: 99%

Parametric study of the conditions of supershear crack propagation in brittle materials

Shilko

Psakhie

Popov

2015

AIP Conference Proceedings

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“…High-rate shear loading of the crystallite can lead to the formation of vortex motion of atoms in the region of symmetric tilt GBs [19,20]. The dimensions of the vortices in diameter are several lattice parameters and are characterized by significant atomic displacements not only in the direction of loading, but also in the GB plane.…”

Section: Introductionmentioning

confidence: 99%

Regularities of Structural Rearrangements in Single- and Bicrystals Near the Contact Zone

Zolnikov

Крыжевич

Korchuganov

2020

Springer Tracts in Mechanical Engineering

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The chapter is devoted to the analysis of the features of local structural rearrangementsin nanostructured materialsunder shear loadingand nanoindentation. The study was carried out using molecular dynamics-based computer simulation. In particular, we investigated the features of symmetric tilt grain boundary migration in bcc and fcc metals under shear loading. The main emphasis was on identifying atomic mechanisms responsible for the migration of symmetric tilt grain boundaries. We revealed that grain boundaries of this type can move with abnormally high velocities up to several hundred meters per second. The grain boundary velocity depends on the shear rate and grain boundary structure. It is important to note that the migration of grain boundary does not lead to the formation of structural defects. We showed that grain boundary moves in a pronounced jump-like manner as a result of a certain sequence of self-consistent displacements of grain boundary atomic planes and adjacent planes. The number of atomic planes involved in the migration process depends on the structure of the grain boundary. In the case of bcc vanadium, five planes participate in the migration of the Σ5(210)[001] grain boundary, and three planes determine the Σ5(310)[001] grain boundary motion. The Σ5(310)[001] grain boundary in fcc nickel moves as a result of rearrangements of six atomic planes. The stacking order of atomic planes participating in the grain boundary migration can change. A jump-like manner of grain boundary motion may be divided into two stages. The first stage is a long time interval of stress increase during shear loading. The grain boundary is motionless during this period and accumulates elastic strain energy. This is followed by the stage of jump-like grain boundary motion, which results in rapid stress drop. The related study was focused on understanding the atomic rearrangements responsible for the nucleation of plasticity near different crystallographic surfaces of fcc and bcc metals under nanoindentation. We showed that a wedge-shaped region, which consists of atoms with a changed symmetry of the nearest environment, is formed under the indentation of the (001) surface of the copper crystallite. Stacking faults arise in the (111) atomic planes of the contact zone under the indentation of the (011) surface. Their escape on the side free surface leads to a step formation. Indentation of the (111) surface is accompanied by nucleation of partial dislocations in the contact zone subsequent formation of nanotwins. The results of the nanoindentation of bcc iron bicrystal show that the grain boundary prevents the propagation of structural defects nucleated in the contact zone into the neighboring grain.

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“…At the same time detailed information on the dynamics of structural changes in the surface layer upon irradiation and relaxation of the material can be obtained on the basis of computer simulation methods [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Features of structural changes in the near-surface aluminum layer under various schemes of ion implantation

Крыжевич¹,

Zolnikov²,

Korchuganov³

2017

AIP Conference Proceedings

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Abstract. The molecular dynamics simulation of structural rearrangements in the surface layer of aluminum samples under ion implantation of various intensities was carried out. The features of the internal structure and the crystallographic orientation of the irradiated crystallite were taken into account. To describe the interatomic interaction many-body potentials obtained in the framework of the embedded atom method were used. Irradiation of the {100} surface results in much less number of formed defects than irradiation of the {110} and {111} ones. When irradiating surfaces with beams of relatively low energy grains remain unchanged in the surface region and the formation of stacking faults was not observed. At a high intensity of irradiation, the near-surface layer of the crystallite melts. In the absence of heat removal, the centers of crystallization become grains lying on the boundary of the solid and liquid phases. Those grains increase due to the adjustment of the atoms of the liquid phase to their lattice. As a result, the grain size in the near-surface region increases.

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Possibility of a vortex mechanism of displacement of the grain boundaries under high-rate shear loading

Cited by 28 publications

References 1 publication

Parametric study of the conditions of supershear crack propagation in brittle materials

Parametric study of the conditions of supershear crack propagation in brittle materials

Regularities of Structural Rearrangements in Single- and Bicrystals Near the Contact Zone

Features of structural changes in the near-surface aluminum layer under various schemes of ion implantation

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