Atomistic investigation of the T-stress effect on fracture toughness of copper and aluminum single crystals

Lee, Gi Hun; Chung, Young Jin; Na, Sang Min; Beom, Hyeon Gyu

doi:10.1007/s12206-018-0729-0

Cited by 11 publications

(5 citation statements)

References 40 publications

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“…[10,41] Also, it is within the range of expected "upper" and "lower" limit of K IC , that is, 1.08 MPa√m and 0.767 MPa√m, of which the first is evaluated by using density functional theory analyses including lattice trapping, while the second is the theoretical value provided by Griffith's criterion. [45] Going back to the results of Figure 5, the normalized K If are plotted against the length of the singular stress field from FE analyses Λ K . It should be recalled that FE analyses are conducted based on the failure conditions obtained from MS analyses.…”

Section: Discussionmentioning

confidence: 99%

“…For the sake of clarity, it should be mentioned that the FE analyses give slightly larger stresses. A hypothesis is that employment, eventually, of two‐parameters model or inclusion of the T‐stress would correct the differences . Going back to the results of Figure , the normalized K If are plotted against the length of the singular stress field from FE analyses Λ K .…”

Section: Discussionmentioning

confidence: 99%

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On the Crack‐Tip Region Stress Field in Molecular Systems: The Case of Ideal Brittle Fracture

Gallo

2019

Advcd Theory and Sims

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Continuum-based fracture mechanics breaks down at the nanoscale where the discrete nature of atoms cannot be neglected. Intriguingly, this work shows that the concept of stress intensity factor is still valid if the atoms are modeled. Molecular statistics simulations are conducted on single-edge cracked samples of ideal brittle silicon, varying the size until few nanometers. The local virial stress, derived as the functional derivative of the free energy of a molecular system with respect to the deformation tensor, is used as a measure of the mechanical stress at the atomic level. Then, stress intensity factor at failure is evaluated. The results show that regardless of the size, the atomistic stress field varies according to the classical 1/r 0.5 relation, and discrete stress intensity factors can be derived for all the geometries. Continuum values, in contrast, fail to describe the fracture when the length of the singular stress field is smaller than 4-5 times the fracture process zone. Thus, this work shows that the stress intensity factor from atomic stress may be useful to describe the fracture criterion at extremely small dimensions, provided that virial stress is accepted as a representation of mechanical stress at the atomic level.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

On the Crack‐Tip Region Stress Field in Molecular Systems: The Case of Ideal Brittle Fracture

Gallo

2019

Advcd Theory and Sims

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“…Indeed, at a very small scale, the simplification of a body as continuum and homogeneous may not hold, and the discrete nature of atoms should be considered [6][7][8]. Clarification of these aspects could not only bring enormous development in the field of nanotechnology, but macroscale could benefit as well, e.g., multi-scale modeling of fatigue with focus on short cracks and interaction with local micro-structure [9,10], atomistic investigation of stresses, strains and grain boundaries [11], fracture properties of advanced materials [12,13], experimental evaluation of fatigue curve of microscale samples [14].…”

Section: Introductionmentioning

confidence: 99%

Brittle Failure of Nanoscale Notched Silicon Cantilevers: A Finite Fracture Mechanics Approach

Gallo

Sapora

2020

Applied Sciences

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The present paper focuses on the Finite Fracture Mechanics (FFM) approach and verifies its applicability at the nanoscale. After the presentation of the analytical frame, the approach is verified against experimental data already published in the literature related to in situ fracture tests of blunt V-notched nano-cantilevers made of single crystal silicon, and loaded under mode I. The results show that the apparent generalized stress intensity factors at failure (i.e., the apparent generalized fracture toughness) predicted by the FFM are in good agreement with those obtained experimentally, with a discrepancy varying between 0 and 5%. All the crack advancements are larger than the fracture process zone and therefore the breakdown of continuum-based linear elastic fracture mechanics is not yet reached. The method reveals to be an efficient and effective tool in assessing the brittle failure of notched components at the nanoscale.

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“…Moreover, some publications are focused on the estimation of the fracture properties of single crystal Cu by similar approaches. Lee et al [18] used the interatomic potential function of the embedded-atom method to model face-centered cubic structures and to analyze the mode-I fracture behavior under various magnitudes of T-stress. The fractal theory is adopted to interpolate the surface roughness and morphology influence between the Cu rigid plane and elasto-plastic rough substrate [19].…”

Section: Introductionmentioning

confidence: 99%

Interactive Field Effect of Atomic Bonding Forces on the Equivalent Elastic Modulus Estimation of Micro-Level Single-Crystal Copper by Utilizing Atomistic-Continuum Finite Element Simulation

Lee

2020

Molecules

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This study uses the finite element analysis (FEA)-based atomistic-continuum method (ACM) combined with the Morse potential of metals to determine the effects of the elastic modulus (E) of a given example on atomic-level single-crystal copper (Cu). This work aims to overcome the estimated drawback of a molecular dynamic calculation applied to the mechanical response of macro in-plane-sized and atomic-level-thick metal-based surface coatings. The interactive energy of two Cu atoms within a face-centered metal lattice was described by a mechanical response of spring stiffness. Compared with the theoretical value, the parameters of the Morse potential dominated the predicted accuracy through the FEA-based ACM. Moreover, the analytic results indicated that the effective E of a single-crystal Cu was significantly sensitive to the given range of the interactive force field among atoms. The reliable elastic moduli of 86.8, 152.6, and 205.2 GPa along the Cu(100), Cu(110), and Cu(111) orientations of the Cu metal were separately acquired using the presented FEA-based ACM methodology.

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Atomistic investigation of the T-stress effect on fracture toughness of copper and aluminum single crystals

Cited by 11 publications

References 40 publications

On the Crack‐Tip Region Stress Field in Molecular Systems: The Case of Ideal Brittle Fracture

On the Crack‐Tip Region Stress Field in Molecular Systems: The Case of Ideal Brittle Fracture

Brittle Failure of Nanoscale Notched Silicon Cantilevers: A Finite Fracture Mechanics Approach

Interactive Field Effect of Atomic Bonding Forces on the Equivalent Elastic Modulus Estimation of Micro-Level Single-Crystal Copper by Utilizing Atomistic-Continuum Finite Element Simulation

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