scholarly journals Grain Boundary Design for Advanced Materials on the Basis of the Relationship Between Texture and Grain Boundary Character Distribution (GBCD)

1993 ◽  
Vol 20 (1-4) ◽  
pp. 195-216 ◽  
Keyword(s):  
Grain Boundary ◽  
Polycrystalline Materials ◽  
Grain Boundary Character Distribution ◽  
Bulk Properties ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution ◽  
And Performance ◽  
And Control ◽  
The Relationship

On the basis of recent knowledge of structure-dependent boundary properties, the design and control of boundary-related bulk properties and performance of advanced polycrystalline materials are discussed. The grain boundary character distribution (GBCD) which has been recently introduced as a new microstructural factor is shown to be a powerful tool for designing and controlling the bulk properties in polycrystalline materials. The relationship between texture and GBCD has been discussed in connection with other microstructural factors associated with grain boundaries. It has been shown that the relationship between texture and GBCD can provide an important clue to the grain boundary design and control for polycrystalline materials with desirable properties and performance. The present paper shows recent successful achievement of toughening of brittle materials by controlling texture and GBCD. The potential and prospective of the grain boundary design and control for functional materials are also discussed.

SEM-ECP Analysis of Grain-Boundary Character Distribution in Polycrystalline Materials

1996 ◽  
Vol 54 ◽  
pp. 354-355
Author(s):  
Tadao Watanabe
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Polycrystalline Materials ◽  
Grain Boundary Character Distribution ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

As demonstrated early 1980’s (1), the scanning electron rnicrocopy-electron channelling pattern (SEM-ECP) technique is very powerful in determination of orientation of individual grains and the character of grain boundaries in polycrystalline materials. Figure 1(a) and (b) show SEM and ECP images of a grain boundary in polycrystal line iron-6.5 mass % silicon ribbon produced by rapid solidification and subsequent annealing. We can intuitively recognize from the SEM-ECP image that the character of the boundary is of <100> tilt type with about 7° misorientation angle. This kind of direct observation is very useful for a study of grain boundary migration and grain growth.This paper discusses advantages of the SEM-ECP technique for the precise determination of the character of grain boundary and for statistical analysis of grain boundaries to bridge roles of individual grain boundaries and bulk properties in a polycrystal. The new microstructural parameter associated with grin boundary termed “grain boundary character distribution (GBCD)” which was introduced by the present author (2,3) and has been utilized in designing and engineering grain boundaries in order to produce desirable and/or high bulk performance in polycrystalline materials (4,5). GBCD describes the type and the frequency of different types of grain boundaries, ie. random general boundaries and special boundaries like low-angle boundaries and low Σ coincidence boundaries.

scholarly journals Critical events, entropy, and the grain boundary character distribution

2011 ◽  
Vol 83 (13) ◽  
Author(s):  
K. Barmak ◽  
E. Eggeling ◽  
M. Emelianenko ◽  
Y. Epshteyn ◽  
D. Kinderlehrer ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Character Distribution ◽  
Critical Events ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

The Grain Boundary Diffusion Kinetics in Nanocrystalline Zirconia

1996 ◽  
Vol 458 ◽  
Author(s):  
A. P. Zhilyaev ◽  
V. Y. Gertsman ◽  
J. A. Szpunar
Keyword(s):  
Grain Boundary ◽  
Oxidation Rate ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Different Types ◽  
Nanocrystalline Zirconia ◽  
Boundary Character Distribution

ABSTRACTIt is expected that the grain boundary diffusion is the principal contributor to the transport properties of nanocrystalline zirconia, and that it controls the oxidation kinetics and hydrogen permeation. This process depends on the grain boundary character distribution (i.e. the fractions of different grain boundary types) and on the topological characteristics of the grain boundary network. Modeling of the random walk problem on a planar honeycomb network for different types of the grain boundary misorientation distributions (GBMD) in nanocrystalline zirconia film is presented in the current paper. The GBMD was calculated using the model texture. Changes of the oxidation rate for different types of the grain boundary character distribution and different ratios of the bulk and grain boundary diffusion coefficients are analyzed. In this study it was found that an increase of the frequency of low energy boundaries lowers the oxidation rate.

scholarly journals Influence of Processing Method on the Grain Boundary Character Distribution and Network Connectivity

1999 ◽  
Vol 586 ◽  
Author(s):  
Adam J. Schwartz ◽  
Mukul Kumar ◽  
Wayne E. King
Keyword(s):  
Grain Boundary ◽  
Annealing Temperature ◽  
Thermomechanical Processing ◽  
Processing Method ◽  
Grain Boundary Character Distribution ◽  
Deformation Path ◽  
Inconel 600 ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

ABSTRACTThere exists a growing body of literature that correlates the fraction of “special” boundaries in a microstructure, as described by the Coincident Site Lattice Model, to properties such as corrosion resistance, intergranular stress corrosion cracking, creep, etc. Several studies suggest that the grain boundary character distribution (GBCD), which is defined in terms of the relative fractions of “special” and “random” grain boundaries, can be manipulated through thermomechanical processing. This investigation evaluates the influence of specific thermomechanical processing methods on the resulting GBCD in FCC materials such as oxygenfree electronic (ofe) copper and Inconel 600. We also demonstrate that the primary effect of thermomechanical processing is to reduce or break the connectivity of the random grain boundary network. Samples of ofe Cu were subjected to a minimum of three different deformation paths to evaluate the influence of deformation path on the resulting GBCD. These include: rolling to 82% reduction in thickness, compression to 82% strain, repeated compression to 20% strain followed by annealing. In addition, the influence of annealing temperature was probed by applying, for each of the processes, three different annealing temperatures of 400, 560, and 800°C. The observations obtained from automated electron backscatter diffraction (EBSD) characterization of the microstructure are discussed in terms of deformation path, annealing temperature, and processing method. Results are compared to previous reports on strainannealed ofe Cu and sequential processed Inconel 600. These results demonstrate that among the processes considered, sequential processing is the most effective method to disrupt the random grain boundary network and improve the GBCD.

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