Atomistic simulation of shear-coupled motion of [1 1 0] symmetric tilt grain boundary in α-iron

Yin, Jian; Wang, Yi; Yan, Xiaohan; Hou, Huaiyu; Wang, Jing Tao

doi:10.1016/j.commatsci.2018.02.039

Cited by 11 publications

(10 citation statements)

References 35 publications

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“…The magnitude of the coupling factor depends primarily on the structure of the GB and can vary with the crystallite temperature for some GBs [13]. It is approximately equal to 1 for the GB considered in this paper.…”

Section: Gbs Migrationmentioning

confidence: 95%

“…The shear-coupled GB motion is an important mechanism for the plasticity of nanocrystalline metals. Simulation of the behavior of the ∑9 [110](221) and ∑17 [110](223) symmetric tilt GBs in iron crystallite under shear loading is carried out using the molecular dynamics method in [13]. The authors investigated the effect of temperature and strain rate on the shear-coupled GB motion.…”

Section: Introductionmentioning

confidence: 99%

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Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

2019

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Molecular dynamics simulations of structural rearrangements in nanocrystalline Ni with the symmetric tilt grain boundary (GB) ∑5 (310) [001] under shear loading were conducted. It was found that GB can be displaced in the direction perpendicular to the shear loading direction. To activate the displacement, it is necessary to reach the threshold value of the shear stress. The GB displacement is abrupt and is due to a certain sequence of displacements of the atomic planes adjacent to the GB. These planes are successively rebuilt from the structure of one grain to the structure of another grain in the process of GB migration. The velocity of GB migration can reach several hundred meters per second and depends on the rate of shear loading. The use of periodic boundary conditions prevents the rotations of the grains. As the simulated tilt GB is symmetric, both of the crystallite grains will have the same shear moduli in the direction of the applied loading. The shear loading of the crystallite with such a structure does not lead to any volume driving forces. The GB displacement was entirely due to the coupling effect. The shear stress curve as a function of time has a sawtooth shape. The GB experiences displacement upon reaching the maximum value of the applied shear stresses. Despite the high stress values, the GB displacement did not cause the nucleation of the defect structure in the crystallite. The GB migration is accompanied by a change in the volume of atoms involved in structural rearrangements.

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Section: Gbs Migrationmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

2019

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“…The simulation procedure included three stages: Setup of atoms, relaxation, and deformation, which was the same as other research work [31,32,33,37] on the boundary migration. During setup, atoms were arranged to produce crystallographic microstructure with two coherent ETBs existed between the matrix and twin blocks in cell.…”

Section: Methodsmentioning

confidence: 99%

“…Despite many efforts on probing the twinning and detwinning behaviors in Mg alloys, the TB migration mechanism was still unclear. Therefore, in this paper, the shear-couple grain migration method which had been successfully used in Face-Centered Cubic and Body-Centered Cubic materials [30,31,32,33,34,35,36,37] was carried out by molecular dynamics simulation. The influence of the strain rates and loading directions on the growth and shrinkage mechanism of {10true1¯2} extension twin are studied.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulation on the Twin Boundary Migration in Mg under Shear Deformation

Song

Wang

et al. 2019

Materials

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In this paper, the {10true1¯2} twinning and detwinning was studied by molecular dynamics simulation under different shear directions and strain rates. The results showed that the twin was thickened under [true1¯011] shear direction and shrunken with shearing in the opposite direction. The critical resolved shear stress of {10true1¯2} twin boundary migration increased with the increase of the strain rate. By analyzing the atom’s displacement, it was concluded that the {10true1¯2} twin migration was achieved by both the shear and the atomic shuffling. Every atom would be affected by the shear, and different shear directions would cause opposite move directions, which led to twinning or detwinning. The atom shuffling was only used for adjusting the glide twin boundary and mirror-symmetric twin boundary structure evolution.

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“…For example in fcc Cu, the simulations demonstrated a strong effect of the transitions on self and impurity diffusion [57,55,56], segregation [57] as well as GB migration and shear strength [90]. A recent study investigated coupled motion of two [110] symmetric tilt boundaries in bcc iron and demonstarted abrupt changes in GB migration and shear stress with increasing temperature [91]. These results are consistent with multiple GB phases and GB phase transitions demontrated in our study for the same family of symmetric tilt boundaries in a different bcc metal.…”

Section: [110] Tilt Boundariesmentioning

confidence: 99%

Structures and transitions in bcc tungsten grain boundaries and their role in the absorption of point defects

et al. 2018

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We use atomistic simulations to investigate grain boundary (GB) phase transitions in elemental body-centered cubic (bcc) metal tungsten. Motivated by recent modeling study of grain boundary phase transitions in [100] symmetric tilt boundaries in face-centered cubic (fcc) copper, we perform a systematic investigation of [100] and [110] symmetric tilt high-angle and low-angle boundaries in bcc tungsten. The structures of these boundaries have been investigated previously by atomistic simulations in several different bcc metals including tungsten using the the γ-surface method, which has limitations. In this work we use a recently developed computational tool based on the USPEX structure prediction code to perform an evolutionary grand canonical search of GB structure at 0 K. For high-angle [100] tilt boundaries the ground states generated by the evolutionary algorithm agree with the predictions of the γ-surface method. For the [110] tilt boundaries, the search predicts novel high-density low-energy grain boundary structures and multiple grain boundary phases within the entire misorientation range. Molecular dynamics simulation demonstrate that the new structures are more stable at high temperature. We observe first-order grain boundary phase transitions and investigate how the structural multiplicity affects the mechanisms of the point defect absorption. Specifically, we demonstrate a two-step nucleation process, when initially the point defects are absorbed through a formation of a metastable GB structure with higher density, followed by a transformation of this structure into a GB interstitial loop or a different GB phase.

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Atomistic simulation of shear-coupled motion of [1 1 0] symmetric tilt grain boundary in α-iron

Cited by 11 publications

References 35 publications

Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

Atomistic Simulation on the Twin Boundary Migration in Mg under Shear Deformation

Structures and transitions in bcc tungsten grain boundaries and their role in the absorption of point defects

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Atomistic simulation of shear-coupled motion of [1 1 0] symmetric tilt grain boundary in α-iron

Cited by 11 publications

References 35 publications

Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

Atomic mechanisms of high-speed migration of symmetric tilt grain boundaries in nanocrystalline Ni

Atomistic Simulation on the Twin Boundary Migration in Mg under Shear Deformation

Structures and transitions in bcc tungsten grain boundaries and their role in the absorption of point defects

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Atomistic simulation of shear-coupled motion of [1 1 0] symmetric tilt grain boundary in α-iron