Grain boundary shear–migration coupling—I. In situ TEM straining experiments in Al polycrystals

Interfacial anisotropy complicates the prediction of microstructural evolution, particularly ir extreme cases for which the presence of facets and corners prevents the application of classical notions of grain-boundary curvature. Although there has been much effort at incorporating anisotropic grain-boundary properties, including faceted geometries, into computational approaches for microstructural evolution, at present our mechanistic understanding of the behavior of facets anc their junctions remains limited. In this presentation, we investigate the development of faceted boundaries between Σ=3 <111> oriented grains in epitaxially deposited gold thin films. This system is well suited tc experimental studies of facet evolution since the crystallography and structure of the boundaries is already well understood. It is well known that “double-positioning” of epitaxially aligned <111> grains on a surface of three-fold or six-fold symmetry results in a microstructure composed of grains in two twin-related (Σ=3) variants that are separated by facets running vertically through the film and forming 120 degree corners [1,2].

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Evidence from in situ TEM straining studies for the mechanism of transfer of slip across a grain boundary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010514x ◽

1988 ◽

Vol 46 ◽

pp. 616-617

Author(s):

I.M. Robertson ◽

T.C. Lee ◽

P. Rozenak ◽

G.M. Bond ◽

H.K. Birnbaum

Keyword(s):

Mechanical Properties ◽

Grain Boundary ◽

Transfer Process ◽

Boundary Structure ◽

In Situ Tem ◽

Boundary Dislocation ◽

Dislocation Source ◽

Structure Changes ◽

Matrix Dislocation

The bulk mechanical properties of a material will primarily be determined by the integrity of the grain boundaries which depends on the local chemistry and the boundary structure. Changes in the composition of the boundary may affect the strength of the atomic bonds through a redistribution of the electrons; this effect has been predicted from theoretical calculations1 but not determined experimentally. The structure of the boundary will be determined by the mismatch between the adjoining grains and it will affect the mechanism by which strain is transferred through the boundary. From static observations of the interaction between matrix and grainboundary dislocations the following scenario has been constructed for the transfer process through random boundaries; The interaction between the incoming matrix dislocation and those in the grain boundary cause the emission of a dislocation from a grain-boundary dislocation source into the adjacent grain. To preserve the contiguity of the grain boundary a residual dislocation will be created within the grain boundary.

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Evaluation of Strain Effects on Grain Boundary Engineering Mechanisms Using In Situ TEM

10.17918/etd-4331 ◽

2021 ◽

Author(s):

Asher Calvin Leff

Keyword(s):

Grain Boundary ◽

In Situ Tem ◽

Grain Boundary Engineering ◽

Strain Effects

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Dislocation Interaction with a Σ=3 Grain Boundary Observed by in situ TEM

Materials Science Forum ◽

10.4028/www.scientific.net/msf.294-296.397 ◽

1998 ◽

Vol 294-296 ◽

pp. 397-400 ◽

Cited By ~ 2

Author(s):

T. Vystavěl ◽

Alain Jacques ◽

A. Gemperle ◽

J. Gemperlová ◽

A. George

Keyword(s):

Grain Boundary ◽

In Situ Tem ◽

Dislocation Interaction

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Grain Boundary Responses to Local and Applied Stress: An In Situ TEM Deformation Study

MRS Proceedings ◽

10.1557/proc-976-0976-ee02-01 ◽

2006 ◽

Vol 976 ◽

Author(s):

Bryan Miller ◽

Jamey Fenske ◽

Dong Su ◽

Chung-Ming Li ◽

Lisa Dougherty ◽

...

Keyword(s):

Electron Microscope ◽

Grain Boundary ◽

Grain Boundaries ◽

Grain Growth ◽

Transmission Electron Microscope ◽

In Situ Tem ◽

Deformation Twins ◽

Transmission Electron ◽

Dislocation Interactions

AbstractDeformation experiments at temperatures between 300 and 750 K have been performed in situ in the transmission electron microscope to investigate dislocation interactions and reactions with grain boundaries and other obstacles. Dislocations, both partial and perfect, as well as deformation twins have been observed being emitted from grain boundaries and, in some cases, even the same grain boundary. The ejection of dislocations from the grain boundary can result in its partial or total annihilation. In the latter case, the disintegration of the grain boundary was accompanied by grain growth and a change in misorientation.

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