On the Determination of Grain Boundary Structure Using X-RAY Diffraction

1988 ◽  
Vol 138 ◽  
Author(s):  
R. W. Balluffi ◽  
I. Majid ◽  
P. D. Bristowe
Keyword(s):  
Grain Boundary ◽  
Boundary Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Boundary Structure

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.

Rodrigues-Frank Space Representations of Fiber Texture

1995 ◽  
Vol 403 ◽  
Author(s):  
Krishna Rajan ◽  
Ronald Petkie
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Crystallographic Orientation ◽  
Fiber Texture ◽  
Boundary Structure ◽  
Structure Information ◽  
Grain Boundary Structure ◽  
Specific Determination

AbstractThe concept of fcc fiber texture is examined in the context of Rodrigues-Frank (R-F) representations. Using fiber texture in thin films as the basis of our analysis, it is shown that this approach when combined with grain specific determination of crystallographic orientation provides a useful means of detecting a number of texture components with relatively small grain sampling densities. The application of R-F representations is also shown to be a useful methodology to couple grain boundary structure information with microtexture data.

Grain Boundary Structure and Deformation Defects in Nanostructured Al–Mg Alloys Processed by High Pressure Torsion

2008 ◽  
Vol 584-586 ◽  
pp. 528-534 ◽  
Author(s):  
M. Liu ◽  
Hans Jørgen Roven ◽  
Tamás Ungár ◽  
L. Balogh ◽  
Maxim Yu. Murashkin ◽  
...  
Keyword(s):  
High Pressure ◽  
Grain Boundary ◽  
Line Profile ◽  
High Pressure Torsion ◽  
Boundary Structure ◽  
X Ray ◽  
Grain Boundary Structure ◽  
Average Grain Size ◽  
Deformation Defects ◽  
Non Equilibrium

An Al–0.5 Mg alloy and a commercial AA5182 alloy were subjected to high pressure torsion (HPT) to five turns under pressure of 6 GPa at room temperature. The grain boundary structure and deformation defects were investigated after HPT using high-resolution transmission electron microscopy (HRTEM). Low-angle, high-angle, equilibrium and non-equilibrium grain/subgrain boundaries, twin boundaries, full dislocations, dipoles, microtwins and stacking faults were identified by HRTEM. Extrinsic 60° dislocations in the form of dipoles were frequently observed in non-equilibrium grain/subgrain boundaries. In addition subgrain size distributions and dislocation densities were quantified by x-ray line profile analysis. It was observed that the average grain size decreased from about 120 nm to 55 nm as the Mg content increased from 0.5 to 4.1 wt%. Concomitantly the average stored dislocation density increased from 1.7 to 12.8  1014 m-2. Based on the HRTEM investigations and the x-ray line profile analyses, the deformation mechanism associated with the typical grain boundaries and deformation defects in the aluminium alloys were discussed.

Imaging of Magnetic Steel Filaments with an HB-5 STEM

1981 ◽  
Vol 39 ◽  
pp. 322-323
Author(s):  
I. Y. T. Chan ◽  
H. G. F. Wilsdorf
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Boundary Structure ◽  
X Ray Diffraction ◽  
Iron Carbides ◽  
Similar Composition ◽  
X Ray ◽  
Grain Boundary Structure ◽  
Ion Microscopy ◽  
Magnetic Steel

The tensile strength of polycrystalline steel filaments 0.2-0.6 cm long with diameters between 1 μm and 20μm can be as high as 8 GPa. When compared to steels of similar composition (α-Fe with 1.5 w/o C, 0.8 w/o O) obtained by solidification, they exhibit an exceptional microstructure due to their production by chemical vapor deposition in the presence of a strong magnetic field. Regardless of the diameter, the grain size is between 10 nm and 30 nm. TEM, field ion microscopy, electron and x-ray diffraction studies have shown that within the grains a microdispersion of iron oxides, iron carbides, and carbon exists. Also, it was found in a recent investigation that the boundaries between grains are not sharp and planar but consist of regions about 2 nm wide. The following research was aimed at clarifying the grain boundary structure.

Effects of elastic anisotropy on CTEM dislocation images in L10 alloys: An assessment of the sensitivity computed images to input parameters

1992 ◽  
Vol 50 (2) ◽  
pp. 1438-1439
Author(s):  
Abha Singh ◽  
A.H. King
Keyword(s):  
Grain Boundary ◽  
Image Matching ◽  
Elastic Anisotropy ◽  
Boundary Structure ◽  
Practical Applications ◽  
Grain Boundary Structure ◽  
Ordered Alloys ◽  
Grain Boundary Embrittlement ◽  
Matching Techniques

Ordered alloys have important applications as high temperature structural materials. Grain boundary embrittlement, however, is a major obstacle in their practical applications. The details of grain boundary structure have been suggested to be important in determining the mechanical properties, and it is therefore important to have a better understanding of grain boundary structure in these alloys.Conventional g.b and g.b×U techniques for the determination of Burgers vectors of lattice and grain boundary dislocations are limited by the magnitude of the Burgers vectors and spacing of the dislocations. The dislocations may not be detected if the magnitude of the Burgers vectors is less than 0.05nm or the spacings less than one third of the extinction distance. The strengths of grain boundary dislocations are usually very small, therefore in determining the Burgers vectors of grain boundary dislocations, computer image matching techniques are generally used in conjunction with the usual g.b and g.b×U techniques.

Boundary-structure determination of Ag/Si(111) interfaces by x-ray diffraction

1995 ◽  
Vol 52 (3) ◽  
pp. 1839-1847 ◽  
Author(s):  
R. D. Aburano ◽  
Hawoong Hong ◽  
J. M. Roesler ◽  
K. Chung ◽  
D.-S. Lin ◽  
...  
Keyword(s):  
Structure Determination ◽  
Boundary Structure ◽  
X Ray Diffraction ◽  
X Ray

Two Investigations into Grain Boundary Structure

1977 ◽  
Vol 35 ◽  
pp. 688-691
Author(s):  
P. Humble
Keyword(s):  
Grain Boundary ◽  
Dark Field ◽  
Boundary Structure ◽  
Boundary Dislocation ◽  
Bright Field ◽  
Intrinsic Structure ◽  
Weak Beam ◽  
Grain Boundary Structure ◽  
Independent Information ◽  
Diffraction Patterns

There has been sustained interest over the last few years into both the intrinsic (primary and secondary) structure of grain boundaries and the extrinsic structure e.g. the interaction of matrix dislocations with the boundary. Most of the investigations carried out by electron microscopy have involved only the use of information contained in the transmitted image (bright field, dark field, weak beam etc.). Whilst these imaging modes are appropriate to the cases of relatively coarse intrinsic or extrinsic grain boundary dislocation structures, it is apparent that in principle (and indeed in practice, e.g. (1)-(3)) the diffraction patterns from the boundary can give extra independent information about the fine scale periodic intrinsic structure of the boundary.In this paper I shall describe one investigation into each type of structure using the appropriate method of obtaining the necessary information which has been carried out recently at Tribophysics.

Sign in / Sign up

Export Citation Format

Share Document