The solute atmosphere round a moving dislocation and its dragging stress

Yoshinaga, Hideo; Morozümi, Shotaro

doi:10.1080/14786437108217008

Cited by 107 publications

(38 citation statements)

References 9 publications

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“…8) An imaginary tetragonal lattice was constructed around a dislocation as shown in Fig. 1 and the lattice constant was taken as the jump distance, s, of solute atoms.…”

Section: Simulation To Estimate Dislocation Mobilitymentioning

confidence: 99%

See 1 more Smart Citation

In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

et al. 2002

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“…8) An imaginary tetragonal lattice was constructed around a dislocation as shown in Fig. 1 and the lattice constant was taken as the jump distance, s, of solute atoms.…”

Section: Simulation To Estimate Dislocation Mobilitymentioning

confidence: 99%

“…Secondly mobilities were also estimated by a simulation using the interaction between an edge dislocation and solute atoms in an imaginary tetragonal lattice. 8) The results of TEM observation were compared with the results of simulation. The effect on solid solution hardening caused by W addition and Mo addition is also discussed.…”

Section: Introductionmentioning

confidence: 99%

In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

et al. 2002

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“…Diffusion under uniform stress has been well studied over the years but diffusion in stress fields that vary rapidly over the scale of diffusional hopping distances has been addressed to a much lesser degree [1,2]. Other atomistic studies that consider, for example, solute diffusion near a dislocation, use two-dimensional model crystals which lack the anisotropy that the transition state for diffusion in fcc material possesses [3,4]. Since the continuum stress fields associated with a wide range of defects, particularly dislocations and cracks, are singular in nature, the accurate accounting of diffusion in the stress fields near these singularities may play an important role in establishing the proper dynamics of time-dependent deformation phenomena.…”

Section: Introductionmentioning

confidence: 99%

Modelling diffusion in crystals under high internal stress gradients

Olmsted

Phillips

2004

Modelling Simul. Mater. Sci. Eng.

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Diffusion of vacancies and impurities in metals is important in many processes occurring in structural materials. This diffusion often takes place in the presence of spatially rapidly varying stresses. Diffusion under stress is frequently modelled by local approximations to the vacancy formation and diffusion activation enthalpies which are linear in the stress, in order to account for its dependence on the local stress state and its gradient. Here, more accurate local approximations to the vacancy formation and diffusion activation enthalpies, and the simulation methods needed to implement them, are introduced. The accuracy of both these approximations and the linear approximations are assessed via comparison to full atomistic studies for the problem of vacancies around a Lomer dislocation in Aluminium. Results show that the local and linear approximations for the vacancy formation enthalpy and diffusion activation enthalpy are accurate to within 0.05 eV outside a radius of about 13 Å (local) and 17 Å (linear) from the centre of the dislocation core or, more generally, for a strain gradient of roughly up to 6 × 10 6 m −1 and 3 × 10 6 m −1 , respectively. These results provide a basis for the development of multiscale models of diffusion under highly non-uniform stress.

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“…There are also no associated methods for injecting or extracting point defects into such an atomistic model. Large scale diffusion in the presence of weak stress gradients can be modeled using the diffusion equation, and discrete diffusion (DD) methods can be used when field gradients are stronger [7] and resolution of the concentration on a site-by-site basis is desired [8]. But these methods are inapplicable in and around extended defects since the underlying migration barriers in the defects are unknown and because the defect structure can be changing as point defects are absorbed.…”

Section: Introductionmentioning

confidence: 99%

Multiscale diffusion method for simulations of long-time defect evolution with application to dislocation climb

Baker

Curtin

2016

Journal of the Mechanics and Physics of Solids

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In many problems of interest to materials scientists and engineers, the evolution of crystalline extended defects (dislocations, cracks, grain boundaries, interfaces, voids, precipitates) is controlled by the flow of point defects (interstitial/substitutional atoms and/or vacancies) through the crystal into the defect. Precise modeling of this behavior requires fully atomistic methods in and around the extended defect, but the flow of point defects entering the extended defect region can be treated by coarse-grained methods. Here, a multiscale algorithm is presented to provide this coupling. Specifically, direct accelerated molecular dynamics (AMD) of extended defect evolution is coupled to a diffusing point defect concentration field that captures the long spatial and temporal scales of point defect motion in the presence of the internal stress fields generated by the evolving defect. The algorithm is applied to study vacancy absorption into an edge dislocation in aluminum where, under a sufficient driving stress and vacancy supersaturation, vacancy accumulation in the core leads to nucleation of a double-jog that then operates as a sink for additional vacancies; this corresponds to the initial stages of dislocation climb modeled with explicit atomistic resolution. The method is general and so can be applied to many other problems associated with nucleation, growth, and reaction due to accumulation of point defects in crystalline materials.

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The solute atmosphere round a moving dislocation and its dragging stress

Cited by 107 publications

References 9 publications

In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

In-situ Observation of Dislocation Motion and Its Mobility in Fe-Mo and Fe-W Solid Solutions at High Temperatures.

Modelling diffusion in crystals under high internal stress gradients

Multiscale diffusion method for simulations of long-time defect evolution with application to dislocation climb

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