Peierls stress in face-centered-cubic metals predicted from an improved semi-discrete variation Peierls-Nabarro model

Liu, Guisen; Cheng, Xi; Wang, Jian; Chen, Kaiguo; Shen, Yao

doi:10.1016/j.scriptamat.2016.04.013

Cited by 42 publications

(36 citation statements)

References 34 publications

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“…Here, for simplicity, a uniform h ab g0 is used for all sets of αβfor each dislocation type. Regarding characterization, in GPN modeling of puretype dislocations in Ag, Al, and Cu, h ab g0 were determined by fitting the GPN-based disregistry profiles to MS-based ones [58]. Applying the same approach here would ideally entail characterizing h ab g0 by fitting the PFDD-based disregistry profile to that from DFT.…”

Section: Determination Of the Gradient Energy Coefficients η αβ G0mentioning

confidence: 99%

Ab initio-informed phase-field modeling of dislocation core structures in equal-molar CoNiRu multi-principal element alloys

Beyerlein

2019

Modelling Simul. Mater. Sci. Eng.

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In this work, selecting the equal-molar CoNiRu multi-principal element alloy (MPEA) as a model material, we study dislocation core structures starting from first principles. We begin by sifting through all possible configurations to find those corresponding to elastic stability and energetically favored facecentered cubic (fcc) phases and, then, for these configurations, employ a phase field-based model to predict the extent of dislocations lying within them. The main findings are that for the fcc phase, (i) large variations in atomic configuration for the same chemical composition can cause significant changes in the generalized stacking fault energy surface and (ii) the dispersion in defect fault energies are chiefly responsible for substantial variations in the intrinsic stacking fault (ISF) widths of screw and edge dislocations. For instance, positive the ISF energy can vary by 10 times, with the lower values correlated with entirely Ni and Ru atoms and higher values with only Co and Ru atoms across the slip plane. Variations in lattice parameter and stiffness tensor accompany local differences in atomic configuration are also taken into account but shown to play a lesser role. We find that the dislocation can experience profound variations (3-7-fold changes) in its associated ISF width along its line, with the screw dislocation experiencing a greater variation than the edge dislocation (6.02-43.22 Å for the screw dislocation, and 19.6-62.62 Å for the edge dislocation). We envision that the ab initio-informed phase-field modeling method developed here can be readily adapted to MPEAs with other chemical compositions.

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Section: Determination Of the Gradient Energy Coefficients η αβ G0mentioning

confidence: 99%

Ab initio-informed phase-field modeling of dislocation core structures in equal-molar CoNiRu multi-principal element alloys

Beyerlein

2019

Modelling Simul. Mater. Sci. Eng.

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“…These improved PN models have been examined and extended for predicting core structure and Peierls stress of dislocations in various crystals (Schoeck, 2012(Schoeck, , 2013Wang et al, 2014a), and even for Escaig stress assisted dislocation cross-slip in FCC metals (Lu et al, 2004). Particularly, the recently developed semi-discrete variational Peierls-Nabarro (SVPN) model (Liu et al, 2016) have been demonstrated to obtain a more accurate prediction of core structure and Peierls stress of dislocations in FCC metals, as well as the right trend in the variation of the stacking fault width as the dislocation overcomes the Peierls barrier. In addition, the improved SVPN model can also predict the dislocation profile much more efficiently than atomistic simulations by numerically minimizing the dislocation energy functional.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we apply the improved SVPN model (Liu et al, 2016) to investigate the effects of the Escaig stress on core structure and Peierls stress of dislocations in FCC metals.…”

Section: Introductionmentioning

confidence: 99%

“…We take the edge and screw dislocations in Cu as examples, because highly reliable interatomic potential is available for Cu (Mishin et al, 2001). We also perform MD simulations to exam the results obtained from the SVPN model (Liu et al, 2016). This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

“…This paper is organized as follows. Section 2 describes theoretical background of Escaig stress effects, and computational details of both the improved SVPN model (Liu et al, 2016) and MD simulations. The results are presented and discussed in section 3, followed by a summary in section 4.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quasi-periodic variation of Peierls stress of dislocations in face-centered-cubic metals

Liu

Cheng

Wang

et al. 2017

International Journal of Plasticity

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The Escaig stress, i.e. the shear stress perpendicular to the Burgers vector, modulates the stacking fault area between two partials of a full dislocation, in turn, affects the mobility of the dislocation. In this paper, using the newly improved semi-discrete variational Peierls-Nabarro (SVPN) model we studied the variation of Peierls stress (τ p) of dislocations in face-centered-cubic crystals with respect to the Escaig stress. We found that τ p quasi-periodically oscillates and the oscillation gradually decreases with the increase of Escaig stress. This quasi-periodic variation of τ p can be mathematically described by the combination of a sinusoidal and an exponential function, and further accounted for by the variation of the stacking fault width (SFW) between two partials during their movement under applied stress. For the maximum τ p , SFW is about integral multiples of the Peierls period. For the minimum τ p , SFW is around half-integral multiples of Peierls period. The variation of τ p is associated with the oscillation magnitude of SFW from half-integral multiples to integral multiples of the Peierls period and then back to integral multiples of Peierls period caused by the Escaig stress. Molecular dynamics (MD) simulations further examined quasi-periodic variation of τ p , validating the SVPN model's capability of predicting sophisticated behavior of dislocation under applied stress.

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Deformation in Metals: Insights from ab-initio Calculations

Linda,

Akhtar,

Bhowmick

2023

Proceedings of the International Conference on Metallurgical Engineering and Centenary Celebration

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Peierls stress in face-centered-cubic metals predicted from an improved semi-discrete variation Peierls-Nabarro model

Cited by 42 publications

References 34 publications

Ab initio-informed phase-field modeling of dislocation core structures in equal-molar CoNiRu multi-principal element alloys

Ab initio-informed phase-field modeling of dislocation core structures in equal-molar CoNiRu multi-principal element alloys

Quasi-periodic variation of Peierls stress of dislocations in face-centered-cubic metals

Deformation in Metals: Insights from ab-initio Calculations

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