Plastic flow stress of b.c.c. transition metals and the Peierls potential

Suzuki, Takayoshi; Koizumi, Hirokazu; Kirchner, H. O. K.

doi:10.1016/0956-7151(94)00451-x

Cited by 87 publications

(41 citation statements)

References 27 publications

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“…This development is described in detail in Section 3. Furthermore, the region of the potential where the Peierls barrier reaches its maximum, which is not sampled in 0 K calculations, is chosen to be flat as suggested by the analysis of the effect of this region on the temperature dependence of the yield stress in [41][42][43].…”

Section: Discussionmentioning

confidence: 99%

“…reaches its largest value far away from this maximum and thus equation (7) that provides for the input of data from atomistic studies conveys no information about the Peierls barrier near its maximum. Auspiciously, a helpful information about this region of the Peierls barrier was obtained in [41][42][43] where the thermally activated formation of kink-pairs for various shapes of the Peierls barrier was investigated. The best agreement between calculated temperature dependence of the yield stress and experiments was attained when the top of the Peierls barrier exhibited a flat plateau or even an intermediate local minimum.…”

Section: Symmetry Mapping Functionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Symmetry Mapping Functionmentioning

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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“…The isolated dislocation shows a pathway that is common for many EAM potential that predict an equilibrium compact core: there is a clear metastable core configuration midway along the path which corresponds to the split core 16 , Figure 1(c). This potential shape has been termed the "camel hump" Peierls potential 7,39,40 . The two pathways for the dipole configurations also exhibit a metastable core structure midway along the pathway.…”

Section: A Empirical Potentialsmentioning

confidence: 99%

Peierls potential of screw dislocations in bcc transition metals: Predictions from density functional theory

2013

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It is well known that screw dislocation motion dominates the plastic deformation in body-centeredcubic metals at low temperatures. The nature of the non-planar structure of screw dislocations gives rise to high lattice friction which results in strong temperature and strain rate dependence of plastic flow. Thus, the nature of the Peierls potential, which is responsible for the high lattice resistance, is an important physical property of the material. However, current empirical potentials give a complicated picture of the Peierls potential. Here, we investigate the nature of the Peierls potential using Density Functional Theory in the BCC transition metals. The results show that the shape of the Peierls potential is sinusoidal for every material investigated. Furthermore, we show the magintiude of the potential scales strongly with the energy per-unit-length of the screw dislocation in the material.

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“…Following the result of detailed analysis for b.c.c. metals [13] in which the kink pair formation of screw dislocations controls the flow stress, the second equality of eq. (4), is assumed.…”

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confidence: 99%