Dislocation patterning in fatigued metals as a result of dynamical instabilities

Walgraef, Daniel; Aifantis, Elias C.

doi:10.1063/1.336183

Cited by 210 publications

(111 citation statements)

References 14 publications

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“…Models describing the coupled evolution of dislocation populations in time (t) and space have been initiated by Walgraef and Aifantis [25] and were further developed in the past years in the context of dislocation patterning. A balance equation is written within a small homogenization volume of linear dimension '.…”

Section: Gradient Plasticity and Size Effectsmentioning

confidence: 99%

Geometrically necessary dislocations and strain-gradient plasticity: a few critical issues

2003

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Section: Gradient Plasticity and Size Effectsmentioning

confidence: 99%

Geometrically necessary dislocations and strain-gradient plasticity: a few critical issues

2003

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“…While these models differ with respect to the conceptual framework employed and the way how length scales are introduced, they have in common that the dislocation arrangement is characterized in terms of space-dependent dislocation densities for which balance equations are formulated in a phenomenological manner. In the work of Walgraef and Aifantis, 3,4 the framework of reaction-diffusion systems was used, and space dependencies were introduced through second-order gradient terms in the dislocation densities. Kratochvil proposed to describe spatial interactions in terms of nonlocal expressions either for the flow stress evolution in general ͑''nonlocal hardening''͒ 5 or, more specifically, for the sweeping of edge dislocation dipoles by moving screw dislocations.…”

Section: Introductionmentioning

confidence: 99%

Statistical dynamics of dislocation systems: The influence of dislocation-dislocation correlations

2001

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During plastic deformation of crystalline materials, the collective dynamics of interacting dislocations gives rise to various patterning phenomena. A crucial and still open question is whether the long range dislocationdislocation interactions which do not have an intrinsic range can lead to spatial patterns which may exhibit well-defined characteristic scales. It is demonstrated for a general model of two-dimensional dislocation systems that spontaneously emerging dislocation pair correlations introduce a length scale which is proportional to the mean dislocation spacing. General properties of the pair correlation functions are derived, and explicit calculations are performed for a simple special case, viz pair correlations in single-glide dislocation dynamics. It is shown that in this case the dislocation system exhibits a patterning instability leading to the formation of walls normal to the glide plane. The results are discussed in terms of their general implications for dislocation patterning.

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“…Their formation exhibits the typical self-organized characteristics. The earlier evolution model of these self-organized dislocation structures could be divided into the static model and dynamic model: a representative of the former is the low-energy dislocation structures (LEDS) model based on Taylor-Nabarro lattice proposed by Kuhlmann-Wilsdorf [9]; a representative of the latter is the analytical model of continuous concentration fields of dislocations proposed by Walgraef and Aifantis [10]. But these models could not well reflect the microscopic features in the evolution process of dislocation patterns, namely the conversion of unit dislocation configurations.…”

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Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

Zhongguang

Zhang

2015

Sci. China Mater.

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tively proposed based on stacking fault energy (SFE).As shown in Fig. 1, PSB ladders or walls are a three-dimensional structure. PSB ladders from t he (12 − 1) plane or PSB walls from the (111) plane occupy about 10% of the PSBs by volume. The walls are 0.03-0.25 μm in thickness with a spacing of about 1.3 μm (see Fig. 2) and they consist of numerous dipoles, especially faulted dipole. The socalled faulted dipole consists of four Shockley partial dislocations and three stacking faults. Th e stair-rods lie at the ends of the stacking fault in the secondary slip plane and their relative position are thus fixed. The dipole as a whole can assume an S-or Z-shaped configuration depending on the position of the Shockley partials. In 1976, Antonopoulos et al. [11,12] pointed out that the matrix vein contained both primary edge dipole and faulted dipole, however, the PSBs were almost full of faulted dipoles, which reflected the microstructure evolution of dislocation patterns. On Based on a large number of experimental results available, it is found that not all the fatigued face-centered-cubic (FCC) pure metals can form the classical persistent slip band (PSB)-ladder structure. The formation of the regular dislocation patterns, especially the PSB ladders, follows one unified principle on the dislocation aggregation and evolution. According to the principle, a simple criterion based on stacking fault energy is proposed to judge whether or not the regular PSB ladders in different FCC pure metals can form.

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Dislocation patterning in fatigued metals as a result of dynamical instabilities

Cited by 210 publications

References 14 publications

Geometrically necessary dislocations and strain-gradient plasticity: a few critical issues

Geometrically necessary dislocations and strain-gradient plasticity: a few critical issues

Statistical dynamics of dislocation systems: The influence of dislocation-dislocation correlations

Basic criterion for the formation of self-organized dislocation patterns in fatigued FCC pure metals

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