Interaction Between Lattice Dislocations and Grain Boundaries in FCC Metals and Ordered Compounds

Pestman, B.J.; Hosson, J.T.M. de; Vítek, V.; Schapink, F.W.

doi:10.1051/jphyscol:1990149

Cited by 5 publications

(5 citation statements)

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“…The structural unit model may help us to predict the interaction between the (superpartial) screw dislocation and a long period boundary, if we know the interaction between the dislocation and the delimiting favoured boundaries. The results of a previous pair potential study of the E=57 in L1 2 ordered structure [9] support this conclusion for ordered alloys. However, there are two considerations that have to be kept in mind: first, in the case of absorption in the boundary and splitting into DSC dislocations, the distance of splitting is limited to one type of structural unit; secondly, the minority units can be thought to contain a dislocation core and there can be elastic interaction.…”

Section: Discussionsupporting

confidence: 83%

Atomic Structure Calculations of the Interaction between Lattice Dislocations and Grain Boundaries

et al. 1990

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The interaction between screw dislocations and [1 1 0] symmetric tilt boundaries is investigated by atomistic calculations. In order to study the differences between fcc and ordered alloys and to study the effect of increasing ordering tendency, many-body potentials representing Cu, Cu 3 Au and Ni 3 Al were used. For the ordered alloys, the different possible ordering configurations of the boundaries that were studied are discussed.

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Section: Discussionsupporting

confidence: 83%

Atomic Structure Calculations of the Interaction between Lattice Dislocations and Grain Boundaries

et al. 1990

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“…However, based on LRB Criterion 3, transmission behaviour would require that the transmitted dislocation have an opposite Burgers vector sign than the incoming dislocation, resulting in an increase in the residual Burgers vector and violating LRB Criterion 2. For shear loading, equation (4) follows LRB Criterion 2 applied to the GB slip plane but equation (5) does not because an alternative deformation path, with transmission of a Shockley partial, could have occurred resulting in a smaller residual Burgers vector. This implies that Criterion 3 is a stronger determinate for nucleation than Criterion 2, at least for conditions with small residual Burgers vectors.…”

Section: Discussionmentioning

confidence: 99%

“…Such GBDs can be localized or spread along the boundary plane [4,5,[16][17][18][19][20][21][22][23][24] depending on the degree of order along the boundary and temperature. Pestman et al showed that transmission versus absorption depends strongly on the structure of the grain boundary and that predictions for long-period boundaries could be possible using the structural unit model [5]. Couzinie et al concluded that recombination of dissociated lattice dislocations is needed prior to the formation of GBDs and that reactions between GBDs in the grain boundary can lead to further relaxation [24].…”

Section: The Angle Between the Lines Of Intersection Between The Incomentioning

confidence: 99%

“…Since dislocation core interactions with grain boundaries are strong and are outside the scope of continuum models, there is no continuum basis from which to derive such critical stresses. Molecular dynamics studies for bicrystals have attempted to derive this parameter [4][5][6], but only for single dislocations, which may not give a complete picture of the transmission phenomena for multiple dislocations.…”

Section: The Angle Between the Lines Of Intersection Between The Incomentioning

confidence: 99%

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The use of hollow-core photonic crystal fibres as biological sensors

et al. 2011

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Dislocation and grain-boundary processes contribute significantly to plastic behaviour in polycrystalline metals, but a full understanding of the interaction between these processes and their influence on plastic response has yet to be achieved. The coupled atomistic discrete-dislocation method is used to study edge dislocation pile-ups interacting with a 11-1 1 3 symmetric tilt boundary in Al at zero temperature under various loading conditions. Nucleation of grainboundary dislocations (GBDs) at the dislocation/grain-boundary intersection is the dominant mechanism of deformation. Dislocation pile-ups modify both the stress state and the residual defects at the intersection, the latter due to multiple dislocation absorption into the boundary, and so change the local grain-boundary/dislocation interaction phenomena as compared with cases with a single dislocation. The deformation is irreversible upon unloading and reverse loading if multiple lattice dislocations absorb into the boundary and damage in the form of microvoids and loss of crystalline structure accumulates around the intersection. Based on these results, the criteria for dislocation transmission formulated by Lee, Robertson and Birnbaum are extended to include the influences of grain-boundary normal stress, shear stress on the leading pile-up dislocation and minimization of step height at the intersection. Two possible yield loci for the onset of GBD nucleation versus compressive stress and relevant shear stresses are derived from the simulations. These results, and similar studies on other boundaries and dislocation characters, guide the formulation of continuum constitutive behaviours for use in discrete-dislocation or strain-gradient plasticity modelling.

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“…Such GBDs can be localized or spread along the boundary plane depending on the character of GB and temperature. Pestman et al [12] showed that the extent of transmission and absorption depends strongly on the structure of the GB. In order to take account of the interaction between pile-ups and tilt GB and the dislocation absorption and propagation within the GB, Dewald and Curtin [13] proposed three additional criteria, including normal compressive stress, the step associated with the residual defect and the influence of partial dislocation on resolved shear stress, based on multiscale simulations CADD.…”

Section: Introductionmentioning

confidence: 98%

A hierarchical dislocation-grain boundary interaction model based on 3D discrete dislocation dynamics and molecular dynamics

Gao

Zhuang

You

2011

Sci. China Phys. Mech. Astron.

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We develop a new hierarchical dislocation-grain boundary (GB) interaction model to predict the mechanical behavior of polycrystalline metals at micro and submicro scales by coupling 3D Discrete Dislocation Dynamics (DDD) simulation with the Molecular Dynamics (MD) simulation. At the microscales, the DDD simulations are responsible for capturing the evolution of dislocation structures; at the nanoscales, the MD simulations are responsible for obtaining the GB energy and ISF energy which are then transferred hierarchically to the DDD level. In the present model, four kinds of dislocation-GB interactions, i.e. transmission, absorption, re-emission and reflection, are all considered. By this methodology, the compression of a Cu micro-sized bi-crystal pillar is studied. We investigate the characteristic mechanical behavior of the bi-crystal compared with that of the single-crystal. Moreover, the comparison between the present penetrable model of GB and the conventional impenetrable model also shows the accuracy and efficiency of the present model.

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Interaction Between Lattice Dislocations and Grain Boundaries in FCC Metals and Ordered Compounds

Cited by 5 publications

References 0 publications

Atomic Structure Calculations of the Interaction between Lattice Dislocations and Grain Boundaries

Atomic Structure Calculations of the Interaction between Lattice Dislocations and Grain Boundaries

The use of hollow-core photonic crystal fibres as biological sensors

A hierarchical dislocation-grain boundary interaction model based on 3D discrete dislocation dynamics and molecular dynamics

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