Annihilation of dislocations during tensile and cyclic deformation and limits of dislocation densities

Eßmann, U.; Mughrabi, H.

doi:10.1080/01418617908234871

Cited by 745 publications

(282 citation statements)

References 43 publications

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“…Considering that reported measured dislocation densities of nominally identical materials can sometimes differ by a factor 2 to 3, the level of correspondence shown in Figure 6 is considered consistent with the model. The present predicted averaged dislocation densities in grains are also broadly consistent with the predicted maximum dislocation densities for pure metals based on models incorporating the assessment of annihilation of individual dislocation of different character (screw and non-screw) [40].…”

Section: Verifying the Modelsupporting

confidence: 73%

“…We define L gen as the total cumulative dislocation linelength generated during the deformation processing. We consider that dislocation are either retained in the grains or subsumed in grain boundaries (existing or new ones) [19,37] or annihilated within the grain [40]. We will consider that the annihilation can be described through a temperature and material dependent annihilation fraction, f an , i.e.…”

Section: Dislocation Generation and Thermally Activated Dislocation Amentioning

confidence: 99%

“…Particularly mutual annihilation of both screw and non-screw dislocations of opposite sign has been evidenced [40]. In the present work we will approximate the rate of dislocation annihilation using the generic exponential relaxation function given by Nes [34]:…”

Section: Dislocation Generation and Thermally Activated Dislocation Amentioning

confidence: 99%

“…vacancy generation following annihilation of dislocations [40], vacancy annihilation, vacancy diffusion, dislocation network growth, self-diffusion.…”

Section: Alternative Models and Mechanismsmentioning

confidence: 99%

See 3 more Smart Citations

Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions

2013

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Section: Verifying the Modelsupporting

confidence: 73%

Section: Dislocation Generation and Thermally Activated Dislocation Amentioning

confidence: 99%

Section: Dislocation Generation and Thermally Activated Dislocation Amentioning

confidence: 99%

“…vacancy generation following annihilation of dislocations [40], vacancy annihilation, vacancy diffusion, dislocation network growth, self-diffusion.…”

Section: Alternative Models and Mechanismsmentioning

confidence: 99%

See 2 more Smart Citations

Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions

2013

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“…. , 12, which is the generalized form of the relation originally suggested by [34]. In this equation, the first term within the parentheses denotes the accumulation , where L ξ is the average dislocation segment length defined by…”

Section: Strain Gradient Crystal Plasticity Formulationmentioning

confidence: 99%

Crystal plasticity based modeling of time and scale dependent behavior of thin films

Ertürk¹,

Gao²,

Bielen³

et al. 2013

GAMM-Mitteilungen

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The micro and sub-micro scale dimensions of the components of modern high-tech products pose challenging engineering problems that require advanced tools to tackle them. An example hereof is time dependent strain recovery, here referred to as anelasticity, which is observed in metallic thin film components of RF-MEMS switches. Moreover, it is now well known that the properties of a thin film material strongly depend on its geometrical dimensions through so-called size effects. A strain gradient crystal plasticity formulation (SGCP) was recently proposed [1][2][3][4], involving a back stress in terms of strain gradients capturing the lattice curvature effect. In the present work, the SGCP model is used in a realistic simulation of electrostatic bending of a free standing thin film beam made of either a pure fcc metal or a particle strengthened Al-Cu alloy. The model capabilities to describe the anelastic and plastic behavior of metallic thin films in comparison with experimentally available data are thereby assessed. Simulation results show that the SGCP model is able to predict a macroscopic strain recovery over time following the load removal. The amount of the anelastic relaxation and the accompanying relaxation times result from the rate dependent modeling approach, the basis of which is phenomenological only. The SGCP model is not fully capable of describing the permanent deformations in an alloy thin beam as observed in electrostatic experiments. Hence, to incorporate realistic time constants and the influence of the microstructure into the mechanical behavior of the thin film material, an improved constitutive law for crystallographic slip is necessary within the SGCP formulation.

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Spontaneous Dislocation Annihilation Explains the Breakdown of the Power Law of Steady State Deformation

Blum¹,

Roters

2001

phys. stat. sol. (a)

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Annihilation of dislocations during tensile and cyclic deformation and limits of dislocation densities

Cited by 745 publications

References 43 publications

Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions

Hardening of pure metals by high-pressure torsion: A physically based model employing volume-averaged defect evolutions

Crystal plasticity based modeling of time and scale dependent behavior of thin films

Spontaneous Dislocation Annihilation Explains the Breakdown of the Power Law of Steady State Deformation

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