Dynamic observation of the collapse process of a stacking fault tetrahedron by moving dislocations

Matsukawa, Y.; Zinkle, S.J.

doi:10.1016/j.jnucmat.2004.04.069

Cited by 76 publications

(49 citation statements)

References 16 publications

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“…After the passages of several dislocations, it may collapse and lose the pinning ability. For example, collapse of stacking fault tetrahedra by the passage of dislocations is both experimentally [20] and computationally [5] observed. This phenomenon is believed to be responsible for the formation of dislocation channel and the localization of plastic flow, which recently invokes attention including some computational studies [19].…”

Section: Effects Of Void Deformation After the Passage Of Severalmentioning

confidence: 99%

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Hatano

Matsui

2005

Phys. Rev. B

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Interactions between an edge dislocation and a void in copper are investigated by means of molecular dynamics simulation. The depinning stresses of the leading partial and of the trailing partial show qualitatively different behaviors. The depinning stress of the trailing partial increases logarithmically with the void radius, while that of the leading partial shows a crossover at 1 nm above which two partials are simultaneously trapped by the void. The pinning angle, which characterizes the obstacle strength, approaches zero when the void radius exceeds 3 nm. No temperature dependence is found in the critical stress and the critical angle. This is attributed to an absence of climb motion. The distance between the void center and a glide plane asymmetrically affects the pinning strength.

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Section: Effects Of Void Deformation After the Passage Of Severalmentioning

confidence: 99%

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Hatano

Matsui

2005

Phys. Rev. B

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“…In the latter case, evidence that the clear bands are formed by the passage of dislocation pile-ups originating from heterogeneities (grain boundaries and cracks) was obtained. In-situ TEM was also used to study the interaction mechanism between individual dislocations and large SFTs [7][8][9] and Frank loops [4]. However, the observations were limited to large defects in very low densities.…”

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confidence: 99%

Atomic-scale plasticity in the presence of Frank loops

Nogaret

Robertson

Rodney

2007

Philosophical Magazine

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“…However, a complete disappearance of SFTs was never observed by MD but was often observed experimentally. It has been suggested the strain rate difference between experiments and MD simulations is the most probable reason for the discrepancies between these two sets of results (23). A mechanism map like Fig.…”

Section: Discussionmentioning

confidence: 97%

“…Consider a similar situation in Cu, where a long-standing and inconclusive inquiry exists to understand the formation of clear channels upon interaction of dislocations with SFT. The SFTs were found to be collapsed by a single moving dislocation in in situ straining TEM experiments (23,24), leading to the formation of defect-free regions. On the other hand, in early MD simulations, the dislocations were found to pass through the perfect SFTs without absorbing them (42).…”

Section: Discussionmentioning

confidence: 99%

“…An issue currently exists in reconciling the results of atomistic MD simulations with experiments because of the time-scale gap between them, whereas it is known that both strain rate and temperature affect the interaction mechanism and critical stresses (1,4,8,12,(20)(21)(22)(23)(24)(25)(26)(27). Methods alternative to MD exist, some based on surveying the potential energy surface coupled with variants of kinetic Monte Carlo (28,29) and some based on escaping from the deep energy minima in dynamics simulations (30)(31)(32).…”

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confidence: 99%

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Mapping strain rate dependence of dislocation-defect interactions by atomistic simulations

Fan¹,

Osetsky

Yip

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

103

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Probing the mechanisms of defect-defect interactions at strain rates lower than 10 6 s −1 is an unresolved challenge to date to molecular dynamics (MD) techniques. Here we propose an original atomistic approach based on transition state theory and the concept of a strain-dependent effective activation barrier that is capable of simulating the kinetics of dislocation-defect interactions at virtually any strain rate, exemplified within 10 −7 to 10 7 s −1 . We apply this approach to the problem of an edge dislocation colliding with a cluster of self-interstitial atoms (SIAs) under shear deformation. Using an activation-relaxation algorithm [Kushima A, et al. (2009) J Chem Phys 130:224504], we uncover a unique strain-ratedependent trigger mechanism that allows the SIA cluster to be absorbed during the process, leading to dislocation climb. Guided by this finding, we determine the activation barrier of the trigger mechanism as a function of shear strain, and use that in a coarsegraining rate equation formulation for constructing a mechanism map in the phase space of strain rate and temperature. Our predictions of a crossover from a defect recovery at the low strainrate regime to defect absorption behavior in the high strain-rate regime are validated against our own independent, direct MD simulations at 10 5 to 10 7 s −1 . Implications of the present approach for probing molecular-level mechanisms in strain-rate regimes previously considered inaccessible to atomistic simulations are discussed.structural materials | mechanical properties | low strain rate atomistic simulation

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Dynamic observation of the collapse process of a stacking fault tetrahedron by moving dislocations

Cited by 76 publications

References 16 publications

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Atomic-scale plasticity in the presence of Frank loops

Mapping strain rate dependence of dislocation-defect interactions by atomistic simulations

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