A Critical Review of the Peierls Mechanism

Guyot, P.; Dorn, J.E.

doi:10.1139/p67-073

Cited by 281 publications

(81 citation statements)

References 9 publications

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“…This repulsive stress, including phonon scattering, impurity drag, and lattice periodicity (e.g., the Peierls potential) acts as an energetic barrier. The energy barrier can be overcome by thermal fluctuations, or when a number of dislocations pile-up to generate a collective repulsive stress field (e.g., [57]). The rate at which obstacles are overcome by thermal fluctuations depends on the vibration frequency of a dislocation f d , which in turn depends on the length of the dislocation.…”

Section: Moving Dislocations At the Ductile-brittle Transitionmentioning

confidence: 99%

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

et al. 2016

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Abstract:Earthquakes are the result of slip along faults and are due to the decrease of rock frictional strength (dynamic weakening) with increasing slip and slip rate. Friction experiments simulating the abrupt accelerations (>>10 m/s 2 ), slip rates (~1 m/s), and normal stresses (>>10 MPa) expected at the passage of the earthquake rupture along the front of fault patches, measured large fault dynamic weakening for slip rates larger than a critical velocity of 0.01-0.1 m/s. The dynamic weakening corresponds to a decrease of the friction coefficient (defined as the ratio of shear stress vs. normal stress) up to 40%-50% after few millimetres of slip (flash weakening), almost independently of rock type. The microstructural evolution of the sliding interfaces with slip may yield hints on the microphysical processes responsible for flash weakening. At the microscopic scale, the frictional strength results from the interaction of micro-to nano-scale surface irregularities (asperities) which deform during fault sliding. During flash weakening, the visco-plastic and brittle work on the asperities results in abrupt frictional heating (flash heating) and grain size reduction associated with mechano-chemical reactions (e.g., decarbonation in CO 2 -bearing minerals such as calcite and dolomite; dehydration in water-bearing minerals such as clays, serpentine, etc.) and phase transitions (e.g., flash melting in silicate-bearing rocks). However, flash weakening is also associated with grain size reduction down to the nanoscale. Using focused ion beam scanning and transmission electron microscopy, we studied the micro-physical mechanisms associated with flash heating and nanograin formation in carbonate-bearing fault rocks. Experiments were conducted on pre-cut Carrara marble (99.9% calcite) cylinders using a rotary shear apparatus at conditions relevant to seismic rupture propagation. Flash heating and weakening in calcite-bearing rocks is associated with a shock-like stress release due to the migration of fast-moving dislocations and the conversion of their kinetic energy into heat. From a review of the current natural and experimental observations we speculate that this mechanism tested for calcite-bearing rocks, is a general mechanism operating during flash weakening (e.g., also precursory to flash melting in the case of silicate-bearing rocks) for all fault rock types undergoing fast slip acceleration due to the passage of the seismic rupture front.

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Section: Moving Dislocations At the Ductile-brittle Transitionmentioning

confidence: 99%

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

et al. 2016

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“…The dislocation models of the formation of kink-pairs, developed originally in [1,2,16,21], all assume that the dislocation glides in a well-defined slip plane and the Peierls barrier is a periodic function of one variable, the coordinate perpendicular to the dislocation line that is the direction of the dislocation glide. Hence, the terms Peierls potential and Peierls barrier have the same V (!)…”

Section: Mesoscopic Dislocation Models Of Kink-pair Formationmentioning

confidence: 99%

“…does work during the activation process, but other constituents of the activation enthalpy may depend on the full stress tensor. This model has been very successful in theoretical treatments of a number of dislocation phenomena involving the lattice resistance to the dislocation glide [13], such as internal friction (Bordoni peak) [1,16,17], thermally activated glide in semiconductors where the high lattice friction arises owing to the covalent bonds [18][19][20] and thermally activated glide of screw dislocations in BCC metals [2,21,22]. The models of the formation of kink-pairs assume implicitly that the Peierls barrier can be identified with the potential energy that varies periodically with the position of the dislocation in its slip plane.…”

Section: Introductionmentioning

confidence: 99%

Multiscale modeling of plastic deformation of molybdenum and tungsten. III. Effects of temperature and plastic strain rate

Gröger

Vítek

2008

Acta Materialia

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In this paper we develop a link between the atomic-level modeling of the glide of 1/2〈111〉 screw dislocations at 0 K and the thermally activated motion of these dislocations via nucleation of pairs of kinks. For this purpose, we introduce the concept of a hypothetical Peierls barrier, which reproduces all the aspects of the dislocation glide at 0 K resulting from the complex response to non-glide stresses and expressed in a compact form by the yield criteria advanced in Part II. To achieve this the barrier is dependent not only on the crystal symmetry and interatomic bonding but also on the applied stress tensor. Standard models are then employed to evaluate the activation enthalpy of kink-pairs formation, which is now also a function of the full applied stress tensor. The transition states theory links then this mechanism with the temperature and strain rate dependence of the yield stress.

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“…As the Peierls stress can be neglected [58] with respect to the range of stresses applied in MD simulations, the drag coefficient was computed directly from Eq. 10.…”

Section: Molecular Dynamics Simulationsmentioning

confidence: 99%

Multiscale modeling of plasticity in a copper single crystal deformed at high strain rates

Chandra

Samal

Chavan

et al. 2015

Plasticity and Mechanics of Defects

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A hierarchical multiscale modeling approach is presented to predict the mechanical response of dynamically deformed (1100 s −1 −4500 s −1 ) copper single crystal in two different crystallographic orientations. An attempt has been made to bridge the gap between nano-, micro-and meso-scales. In view of this, Molecular Dynamics (MD) simulations at nanoscale are performed to quantify the drag coefficient for dislocations which has been exploited in Dislocation Dynamics (DD) regime at the microscale. Discrete dislocation dynamics simulations are then performed to calculate the hardening parameters required by the physics based Crystal Plasticity (CP) model at the mesoscale. The crystal plasticity model employed is based on thermally activated theory for plastic flow. Crystal plasticity simulations are performed to quantify the mechanical response of the copper single crystal in terms of stressstrain curves and shape changes under dynamic loading. The deformation response obtained from CP simulations is in good agreement with the experimental data.

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A Critical Review of the Peierls Mechanism

Cited by 281 publications

References 9 publications

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

Multiscale modeling of plastic deformation of molybdenum and tungsten. III. Effects of temperature and plastic strain rate

Multiscale modeling of plasticity in a copper single crystal deformed at high strain rates

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