Dislocation interactions at the grain boundary in FCC bicrystals: An atomistically-informed dislocation dynamics study

1988 ◽

Vol 46 ◽

pp. 628-629

Author(s):

C. W. Price

Keyword(s):

Dislocation Density ◽

Grain Boundary ◽

Strain Rate ◽

Grain Boundaries ◽

Dislocation Structure ◽

Hot Deformation ◽

Static Recrystallization ◽

High Dislocation Density ◽

High Angle ◽

Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

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Local rules for approximating strong dislocation interactions in discrete dislocation dynamics

Modelling and Simulation in Materials Science and Engineering ◽

10.1088/0965-0393/11/4/312 ◽

2003 ◽

Vol 11 (4) ◽

pp. 609-625 ◽

Cited By ~ 21

Author(s):

K W Schwarz

Keyword(s):

Dislocation Dynamics ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation ◽

Dislocation Interactions

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Dislocation–grain boundary interactions: recent advances on the underlying mechanisms studied via nanoindentation testing

Journal of Materials Research ◽

10.1557/s43578-020-00096-z ◽

2021 ◽

Author(s):

Farhan Javaid ◽

Habib Pouriayevali ◽

Karsten Durst

Keyword(s):

Grain Boundary ◽

Mechanical Response ◽

Displacement Curve ◽

Ambient Conditions ◽

Recent Advances ◽

Slip Transfer ◽

Depth Analysis ◽

Dislocation Interactions ◽

Underlying Mechanisms ◽

Insight Into

Abstract To comprehend the mechanical behavior of a polycrystalline material, an in-depth analysis of individual grain boundary (GB) and dislocation interactions is of prime importance. In the past decade, nanoindentation emerged as a powerful tool to study the local mechanical response in the vicinity of the GB. The improved instrumentation and test protocols allow to capture various GB–dislocation interactions during the nanoindentation in the form of strain bursts on the load–displacement curve. Moreover, the interaction of the plastic zone with the GB provides important insight into the dislocation transmission effects of distinct grain boundaries. Of great importance for the analysis and interpretation of the observed effects are microstructural investigations and computational approaches. This review paper focused on recent advances in the dislocation–GB interactions and underlying mechanisms studied via nanoindentation, which includes GB pop-in phenomenon, localized grain movement under ambient conditions, and an analysis of the slip transfer mechanism using theoretical treatments and simulations. Graphical abstract

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Atomistic and Continuum Studies of Diffusional Creep and Associated Dislocation Mechanisms in thin Films on Substrates

MRS Proceedings ◽

10.1557/proc-779-w4.7 ◽

2003 ◽

Vol 779 ◽

Cited By ~ 2

Author(s):

Markus J. Buehler ◽

Alexander Hartmaier ◽

Huajian Gao

Keyword(s):

Thin Films ◽

Stress Field ◽

Grain Boundary ◽

Large Scale ◽

Strain Relaxation ◽

Dislocation Dynamics ◽

Biaxial Stress ◽

Diffusional Creep ◽

Material Transport ◽

Dynamics Simulations

AbstractMotivated by recent theoretical and experimental progress, large-scale atomistic simulations are performed to study plastic deformation in sub-micron thin films. The studies reveal that stresses are relaxed by material transport from the surface into the grain boundary. This leads to the formation of a novel defect identified as diffusion wedge. Eventually, a crack-like stress field develops because the tractions along the grain boundary relax, but the adhesion of the film to the substrate prohibits strain relaxation close to the interface. This causes nucleation of unexpected parallel glide dislocations at the grain boundary-substrate interface, for which no driving force exists in the overall biaxial stress field. The observation of parallel glide dislocations in molecular dynamics studies closes the theory-experiment-simulation linkage. In this study, we also compare the nucleation of dislocations from a diffusion wedge with nucleation from a crack. Further, we present preliminary results of modeling constrained diffusional creep using discrete dislocation dynamics simulations.

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Dislocation–grain boundary interaction-based discrete dislocation dynamics modeling and its application to bicrystals with different misorientations

Acta Materialia ◽

10.1016/j.actamat.2020.10.052 ◽

2021 ◽

Vol 202 ◽

pp. 88-98

Author(s):

Xu Zhang ◽

Songjiang Lu ◽

Bo Zhang ◽

Xiaobao Tian ◽

Qianhua Kan ◽

...

Keyword(s):

Grain Boundary ◽

Dislocation Dynamics ◽

Dynamics Modeling ◽

Discrete Dislocation Dynamics ◽

Boundary Interaction ◽

Discrete Dislocation

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Grain boundary-dislocation interactions

Bulletin of Materials Science ◽

10.1007/bf02743997 ◽

1984 ◽

Vol 6 (4) ◽

pp. 699-700 ◽

Cited By ~ 1

Author(s):

S Ranganathan

Keyword(s):

Grain Boundary ◽

Boundary Dislocation ◽

Dislocation Interactions

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Plastic Deformation of Textured Zircaloy 2

Materials Science Forum ◽

10.4028/www.scientific.net/msf.702-703.838 ◽

2011 ◽

Vol 702-703 ◽

pp. 838-841

Author(s):

Santosh Kumar Sahoo ◽

V. D. Hiwarkar ◽

Prita Pant ◽

Indradev Samajdar ◽

Karri V. Mani Krishna ◽

...

Keyword(s):

Plastic Deformation ◽

Residual Stresses ◽

Room Temperature ◽

Deformation Behaviour ◽

Dislocation Dynamics ◽

Dynamics Simulation ◽

Distinct Class ◽

Dislocation Interactions ◽

Temperature Deformations ◽

Grain Misorientation

The present study deals with deformation behaviour of textured Zircaloy 2 with two dominant orientations: basal and non-basal. During initial stages (20%), two distinct class of grains were observed – non-deforming/non-fragmenting grains and deforming/fragmenting grains. The so-called non- deforming/non-fragmenting grains remain equiaxed even after 50% of deformation. They also have insignificant in-grain misorientation developments and have more residual stresses. Dislocation dynamics simulation showed that the dislocation interactions/mobility is insignificant in basal orientations at room temperature deformations.

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Equivalent plastic strain gradient plasticity with grain boundary hardening and comparison to discrete dislocation dynamics

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2015.0388 ◽

2015 ◽

Vol 471 (2184) ◽

pp. 20150388 ◽

Cited By ~ 22

Author(s):

E. Bayerschen ◽

M. Stricker ◽

S. Wulfinghoff ◽

D. Weygand ◽

T. Böhlke

Keyword(s):

Plastic Strain ◽

Yield Strength ◽

Grain Boundary ◽

Continuum Model ◽

Equivalent Plastic Strain ◽

Elastic Interaction ◽

Dislocation Dynamics ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation ◽

The Continuum

The gradient crystal plasticity framework of Wulfinghoff et al. (Wulfinghoff et al. 2013 Int. J. Plasticity 51, 33–46. ( doi:10.1016/j.ijplas.2013.07.001 )), incorporating an equivalent plastic strain γ eq and grain boundary (GB) yielding, is extended with GB hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminium-type tricrystal under tensile loading, the new hardening parameter of the continuum model is calibrated. Although the GBs in the discrete simulations are impenetrable, an infinite GB yield strength, corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simulations by using different orientations of the central grain could not be captured. This indicates that the misorientation-dependent elastic interaction of dislocations reaching over the GBs should also be included in the continuum model.

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