Bildung und diffusion von Kinken als grundprozess der Versetzungsbewegung bei der messung der inneren reibung

Seeger, A.; Schiller, P.

doi:10.1016/0001-6160(62)90013-5

Cited by 226 publications

(65 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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%

“…a 0 b#z during the nucleation of the kink-pair. Such saddle-point configuration was first treated theoretically by Seeger [1,16] in the context of studying internal friction. The enthalpy associated with this configuration is…”

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%

See 2 more Smart Citations

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

Gröger

Vítek

2008

Acta Materialia

View full text Add to dashboard Cite

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.

show abstract

Section: Mesoscopic Dislocation Models Of Kink-pair Formationmentioning

confidence: 99%

Section: Mesoscopic Dislocation Models Of Kink-pair Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Gröger

Vítek

2008

Acta Materialia

View full text Add to dashboard Cite

show abstract

“…Thus, the energy barrier for the motion of screw segments, and the attendant Peierls stress, may be expected to be large, and the energy barrier for the motion of edge segments to be comparatively smaller. This suggests that the rate-limiting mechanism for dislocation motion is the thermally activated motion of kinks along screw segments ( [3,4,5]). At sufficiently high temperatures and under the application of a resolved shear stress r > 0, a doublekink may be nucleated with the assistance of thermal activation (e. g., [6,7,8] In the preceeding equations, bis the Burgers vector, p is the dislocation density, ß = l/kBT, kB is Boltzmann's constant, T is the absolute temperature, and VD is the attempt frequency which may be identified with the Debye frequency to a first approximation.…”

Section: Unit Mechanismsmentioning

confidence: 99%

Multiscale modelling of hardening in BCC crystal plasticity

2003

View full text Add to dashboard Cite

: The mechanical behavior of polycrystalline metals can be successfully modeled by macroscopic theories, such as Von Mises plasticity. On the other hand, numerous studies can be performed on the atomic scale, either by atomistic or dislocation dynamics models. The proposed model attempts to bridge those two scales by deriving constitutive relations between slip strains, dislocation densities and resolved shear stresses on crystallographic planes, from mechanisms of deformation playing at the level of the dislocation line. The resulting " mesoscopic " hardening relations are controlled by dislocation self energies and junctions strengths. Temperature and strain rate dependence result from the presence of thermally activated mechanisms such as Peierls barriers or pair annihilation by cross slip. A set of material parameters is identified for Tantalum by fitting the numerical stress strain curves from these tests with experimental results gathered in the literature. These parameters prove to be in very good agreement with the values which can be derived from molecular dynamics computations.

show abstract

“…For instance, Duesbery and Xu [15] have calculated the Peierls stress for a rigid screw dislocation in Mo to be 0.022µ, where µ is the 111 shear modulus, whereas the corresponding Peierls stress for a rigid edge dislocation is 0.006µ, or about one fourth of the screw value. This suggests that the rate-limiting mechanism for dislocation motion is the thermally activated motion of kinks along screw segments ( [16,17,18]). …”

Section: Dislocation Mobility: Double-kink Formation and Thermally Acmentioning

confidence: 99%

Untitled

Cuitiño

Stainier

Wang

et al. 2001

Journal of Computer-Aided Materials Design

View full text Add to dashboard Cite

In this paper we present a modeling approach to bridge the atomistic with macroscopic scales in crystalline materials. The methodology combines identification and modeling of the controlling unit processes at microscopic level with the direct atomistic determination of fundamental material properties. These properties are computed using a many body Force Field derived from ab initio quantum-mechanical calculations. This approach is exercised to describe the mechanical response of high-purity Tantalum single crystals, including the effect of temperature and strain-rate on the hardening rate. The resulting atomistically informed model is found to capture salient features of the behavior of these crystals such as: the dependence of the initial yield point on temperature and strain rate; the presence of a marked stage I of easy glide, specially at low temperatures and high strain rates; the sharp onset of stage II hardening and its tendency to shift towards lower strains, and eventually disappear, as the temperature increases or the strain rate decreases; the parabolic stage II hardening at low strain rates or high temperatures; the stage II softening at high strain rates or low temperatures; the trend towards saturation at high strains; the temperature and strain-rate dependence of the saturation stress; and the orientation dependence of the hardening rate.

show abstract

Bildung und diffusion von Kinken als grundprozess der Versetzungsbewegung bei der messung der inneren reibung

Cited by 226 publications

References 11 publications

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

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

Multiscale modelling of hardening in BCC crystal plasticity

Untitled

Contact Info

Product

Resources

About