Application of Microtexture Measurements in the SEM to Grain Boundary Parameters

This paper discusses how microtexture data, i.e. individual orientations which are measured on a grain and environmentally specific basis, are applied to grain boundary geometrical parameters. Three main areas are addressed: the “interface-plane” scheme for specifying the five degress of freedom of a boundary, comparisons of experimental techniques for data collection, and representation of grain boundary misorientations in Rodrigues-Frank space. Particular attention is paid to electron back-scatter diffraction as a method of probing grain boundary misorientation and the crystallographic orientation of the grain boundary plane.

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Variant Selection in Fcc-to-Bcc Precipitation at Grain Boundaries in Ni-43Cr Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.305 ◽

2005 ◽

Vol 475-479 ◽

pp. 305-308 ◽

Cited By ~ 1

Author(s):

Yoshitaka Adachi ◽

Fu Xing Yin ◽

Kazunari Hakata ◽

Kaneaki Tsuzaki

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Tilt Angle ◽

Boundary Plane ◽

Variant Selection ◽

Orientation Relationships ◽

Boundary Misorientation ◽

Grain Boundary Plane ◽

Grain Boundary Misorientation ◽

Selection Of

Variant selection of bcc-Cr at the grain boundaries in a supersaturated fcc matrix was studied using a Ni-43Cr alloy. The preferentially selected variant was examined as a function of the grain boundary misorientation, the tilt angle between the {111}fcc plane and the grain boundary plane, and the orientation relationships with respect to both of the adjacent matrix grains.

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Incompatibility Stresses and Lattice Rotations Due to Grain Boundary Sliding in Heterogeneous Anisotropic Elasticity

10.20944/preprints201705.0009.v1 ◽

2017 ◽

Author(s):

Thiebaud Richeton

Keyword(s):

Finite Element ◽

Grain Boundary ◽

Triple Line ◽

Grain Boundary Sliding ◽

Boundary Plane ◽

Lattice Rotation ◽

Interface Plane ◽

Grain Boundary Plane ◽

Analytic Expressions ◽

Boundary Sliding

Non-uniform grain boundary sliding can induce strain and rotation incompatibilities at perfectly planar interfaces. Explicit analytic expressions of stress and lattice rotation jumps are thus derived at a planar interface in the general framework of heterogeneous anisotropic thermo-elasticity with plasticity and grain boundary sliding. Both elastic fields are directly dependent on in-plane gradients of grain boundary sliding. It is also shown that grain boundary sliding is a mechanism that may relax incompatibility stresses of elastic, plastic and thermal origin although the latter are not resolved on the grain boundary plane. This relaxation may be a driving force for grain boundary sliding in addition to the traditionally considered local shears on the grain boundary plane. Moreover, the obtained analytic expressions are checked by different kinds of bicrystal shearing finite element simulations allowing grain boundary sliding and where a pinned line in the interface plane aims at representing the effect of a triple junction. A very good agreement is found between the analytic solutions and the finite element results. The performed simulations particularly emphasize the role of grain boundary sliding as a possible strong stress generator around the grain boundary close to the triple line because of the presence of pronounced gradients of sliding.

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Statics and Dynamics of Grain Boundaries in Ni3Al

MRS Proceedings ◽

10.1557/proc-133-137 ◽

1988 ◽

Vol 133 ◽

Author(s):

Diana Farkas

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Cluster Variation Method ◽

Boundary Region ◽

Boundary Plane ◽

Variation Method ◽

Boundary Misorientation ◽

Grain Boundary Plane ◽

Alloy Properties ◽

Experimental Findings

ABSTRACTVarious modeling techniques have been used to study the structure of grain boundaries in ordered compounds, particularly Ni3Al. The techniques include computer simulation, group theoretical analysis and the cluster variation method for high temperature effects. A multiplicity of possible grain boundary structures was analyzed for different misorientations and grain boundary plane location. 1The influence of several alloy properties like atomic size differences and deviation from stochiometry on the occurrence of these different structures is analyzed. The implications of these results for grain boundary misorientation distribution, grain boundary plane location and faceting behavior are discussed and compared to experimental findings. The possibility of orderdisorder transitions in the grain boundary region is also discussed.

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Links Between the Interface Plane Scheme and Grain Boundary Properties

MRS Proceedings ◽

10.1557/proc-458-41 ◽

1996 ◽

Vol 458 ◽

Cited By ~ 1

Author(s):

Valerie Randle

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Knowledge Base ◽

Boundary Plane ◽

Interface Plane ◽

Experimental Knowledge ◽

High Occurrence ◽

Boundary Properties ◽

Plane Scheme

ABSTRACTThis paper describes the current experimental knowledge base concerning the geometry and property relationships at the gram boundary plane. In order to analyse the data the interface-plane scheme is used, and its application is described here. The most important points to emerge from the data are that particular boundary properties - energy, mobility, segregation, precipitation and cracking - correlate with boundary plane types. Recent data illustrating the high occurrence of asymmetrical tilt grain boundaries and importance of low-index grain boundary planes are discussed in more detail.

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Twinning and Interfacial Planes in Copper

Microscopy and Microanalysis ◽

10.1017/s1431927697970173 ◽

1997 ◽

Vol 3 (3) ◽

pp. 224-233 ◽

Cited By ~ 5

Author(s):

Valerie Randle ◽

Mark Caul ◽

Jörn Fiedler

Keyword(s):

Data Collection ◽

Grain Boundary ◽

Lower Energy ◽

Boundary Plane ◽

Sample Population ◽

Experimental Procedure ◽

Grain Boundary Plane ◽

Tilt Boundaries ◽

Annealed Copper ◽

Large Representative

Abstract: This work reports the distribution of a large, representative sample population of grain boundary plane crystallography in pure, annealed copper by use of an improved experimental procedure. The new methodology reduces the laboriousness and improves the accuracy of data collection, and so is described in detail. Analysis of the results concentrates on the Σ3 boundaries, and shows that three-quarters of these were tilt boundaries on the 011 zone. Of these tilt boundaries, nearly half were coherent twins, i.e., on 111/111 planes, or near coherent twins on 23,17,17/775 planes. The high population of the second group is thought to be due to oxygen take-up during annealing. The data in general showed a trend for lower energy Σ3s to occur more frequently. The results were interpreted in terms of boundary energies, local equilibration, and comparisons with previous work in copper and other systems.

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Growth of Grain Boundary Precipitates as a Function of Misorientation in an Al-5 WT% Cu Alloy

MRS Proceedings ◽

10.1557/proc-319-351 ◽

1993 ◽

Vol 319 ◽

Cited By ~ 2

Author(s):

M. A. Cantrell ◽

G. J. Shiflet

Keyword(s):

Grain Boundary ◽

Precipitate Size ◽

Boundary Misorientation ◽

Collector Plate ◽

Cu Alloy ◽

Grain Boundary Plane ◽

Size Evolution ◽

Grain Boundary Misorientation ◽

The Relationship ◽

Reproducible Manner

AbstractThe size evolution of θ phase (CuAl2) precipitates as a function of time was used to study the growth of grain boundary precipitates in an Al-5 wt % Cu alloy. The kinetics were: modeled using the Brailsford and Aaron treatment of the collector plate mechanism. It was found, for a given time, that the size varied in a reproducible manner as a function of misorientation between the grains. Precipitate size was found to vary from 5 x 10-6 cm to 5 x 10-5 cm, while misorientation varied from 20 to 50 degrees for a given heat treatment period. Grain boundary misorientation was determined to be the most important factor influencing precipitate size for a given grain boundary. The grain boundary plane orientation plays a secondary role in the growth of precipitates. From these data, the relationship between grain boundary misorientation and grain boundary diffusion has been determined.

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Measurement of solute segregation to grain boundaries in the AEM: A review

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105096 ◽

1988 ◽

Vol 46 ◽

pp. 606-607

Author(s):

D. B. Williams ◽

A. D. Romig

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Boundary Migration ◽

Grain Boundary Migration ◽

Boundary Misorientation ◽

Collector Plate ◽

Segregation Process ◽

Grain Boundary Misorientation ◽

Structure Boundary ◽

Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

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