On The Study Of Grain Boundary Segregation Using X-Ray Diffraction And Computer Simulation

1991 ◽  
Vol 238 ◽  
Author(s):  
C. A. Counterman ◽  
I. Majid ◽  
P. D. Bristowe ◽  
R. W. Balluffi
Keyword(s):  
Computer Simulation ◽  
Grain Boundary ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Boundary Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Boundary Structure ◽  
Structure Factors ◽  
Diffraction Effects

ABSTRACTThe possibility of studying grain boundary segregation using X-ray diffraction is explored by performing a computer simulation of the diffraction effects expected from the segregation of solute atoms to grain boundaries in two gold alloy systems, i.e. Au-Ag and Au-Ni. Using atomistic Monte-Carlo and molecular statics methods, equilibrium boundary structures are determined and analyzed by computing the grain boundary structure factors. Various changes in both relative and absolute grain boundary structure factors are found which can be directly related to structural and compositional changes due to segregation. In addition, systematic diffraction effects are found as a function of boundary misorientation. The experimental conditions required for verifying these predictions are discussed.

Analysis of boundaries

1987 ◽  
Vol 45 ◽  
pp. 300-303
Author(s):  
Anthony J. Garratt-Reed
Keyword(s):  
Grain Boundary ◽  
Boundary Segregation ◽  
Direct Methods ◽  
Grain Boundary Segregation ◽  
Quality Analysis ◽  
Boundary Structure ◽  
Auger Analysis ◽  
Grain Boundary Structure ◽  
Saturation Coverage ◽  
Depth Sensitivity

As the understanding of the importance of grain boundary structure and chemistry in determining material properties grows, the need for high quality analysis of grain boundary segregation becomes more and more critical. In this paper we shall discuss briefly the three common direct methods of grain boundary analysis. We shall loosely use the term “grain boundary” to include phase boundaries and precipitate interfaces.The earliest technique employed to study grain boundary segregation was Auger electron spectroscopy of intergranular fracture surfaces. Since the depth sensitivity of Auger analysis, is, in general, only a few atomic layers, it is possible in principle to detect only a few percent of saturation coverage of the boundary.

Measuring grain boundary segregation using Wavelength Dispersive X-ray Spectroscopy: Further developments

2011 ◽  
Vol 605 (7-8) ◽  
pp. 848-858 ◽  
Author(s):  
P. Nowakowski ◽  
F. Christien ◽  
M. Allart ◽  
Y. Borjon-Piron ◽  
R. Le Gall
Keyword(s):  
Grain Boundary ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
X Ray

Structure And Composition Of Grain Boundaries In SrTiO3

1999 ◽  
Vol 5 (S2) ◽  
pp. 94-95
Author(s):  
O. Kienzle ◽  
F. Ernst ◽  
Manfred Rühle
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Point Defects ◽  
Coincidence Site Lattice ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Boundary Structure ◽  
Dopant Atoms ◽  
Charged Point ◽  
Atomistic Structure

The electrical properties of SrTiO3 (strontium titanate) ceramics are strongly influenced or even dictated by grain boundary segregation of charged point defects, such as dopant atoms, impurities, vacancies, or self-interstitials. The atomistic structure of the grain boundaries, their energy, and the segregation of point defects mutually depend on each other. Grain boundary segregation of charged point defects induces the formation of space charge layers in the adjoining crystals. In order to investigate the relation between grain boundary structure and composition, grain boundaries in Fedoped SrTiO3 bicrystals and in SrTiO3 ceramics were studied by HRTEM and by AEM with subnanometer resolution.Quantitative HRTEM served to investigate the atomistic structure of Σ=3, (111) grain boundaries in Fe-doped SrTiO3 bicrystals with a doping level of Fe/Ti= 0.04at% (Fig. 1). Analysis of the translation state revealed that the Σ=3, (111) grain boundary has an excess volume: normal to the boundary plane, the spacing between the two crystals exceeds what one would expect from a coincidence site lattice model by (0.06 ±0.01 )nm.

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